A PRACTICAL OF' PftOTOGRAPHY E.J. WALL. THE id FL/\Sri." HAKD CAMERA. id THE FLASH." Benetflnk's lew Hand Camera. Marvellous SPECIMEN PRINT POST FREE. Marvellous Value!!! e Value!!! POST FREE. POST FREE. Possesses All Movements the Beginner Kequires. iC; Carries twelve V4"Plates, with reliable changing arrangement and indi- cator, good quality Achromatic Lens with revolving stops, Vertical and Horizontal View Finders, Time and Instantaneous Shutter with speed regulator, two Bushes and Screw for using camera on stand, neatly covered in black leather with strong carrying handle Size, 9 in. by 4 in. by 7 in. THE id 89, 90, 107&108 Cheapside, LONDON. THE dd FLASH." I IT IS NECESSARY TO SELECT «A Good Camera & Shutter SUITABLE PLATES, FILMS, &c., FOR ADAPTATION TO EITHER OIlD Ol^ J^EW CJimEt^AS, Offer to Amateur or Professional \} i I ^ ^ Photographers and Process '■-V^^'^^'^^ Wnvlf^arc! a Greater Choice and ^ W Olivers. ^ pj^^^ Selection of LIMITED. High-Class Lenses than any other Manufacturer in the World. IMPORTANT NOTICE. The Zeiss and Goerz Patent Anastigmatic Lenses are manu- factured (under License) by ROSS, Ltd., at their Optical Works, Clapham Common, exactly to formula supplied by the patentees ; and the optical glasses and methods of construction are precisely similar to those employed by them, the only difference between the respective lenses being that the Anastigmats made by ROSS, Ltd., are mounted in the English style, and furnished with the Standard apertures of the Royal Photographic Society. ROSS, a 111 New Bond St., London W. 31, Cockspnr St., Charing Cross, S.W. Paris Branch: 35 Boulevards du Temple. Works . Clapham Common, S.W. The A B C of Photography. Amateurs and others are advised to B PLATES, uy ILFORD papers', and FILMS, if they V/are to succeed in their Work. The ILFORD ABC Absolutely Uniform PLATES, Beautifully Perfect PAPERS, Conveniently carried FILMS. OF Alili DEAIiERS. Sole Makers ILFORD, Limited, ILFORD, LONDON, E. Retouching Pencils. Tine finest pencils ever made fot« l^etoachefs at«e li. 6^ C. flattdtmuth*s celebrated I^ohMiMjsioor. The gt^ada^ tion is perfect; made in all degrees, l^etain a morking point longei* than any othei?s. GRAND PRIX AT PARIS 1900. ^^^Mf If you will find L. and C. ^ 'w^r Hardtmuth.DrawingPencils ^^P^ parexcellenceforease^dur- ability, strength and deli- cacy of treatment. Used in ~ all the great Art Schools of Europe. Of stationers and artists cd/ourmen. L. M C. HARDTIUTH, 11 (Jolien Lane E.C. 13 We aim at making ourselves indispensable to all who expose or develop a plate. WATKINS' "sisi._ METERS New. . . Dial i\ Meter llli: r^^^^ Explains W \ r^^^^'A M Itself. i \ ^ / $'1111 n in s. d. Indoor Meter, for hand cameras. No figures . 1 1 Actinometer 3 6 Standard Meter. The only complete one for enlarging 16 Ditto, in aluminium £1 10 Speed Card. Invaluable 0 1^ Eikronometer, for timing development.. . . 10 0 Exposure IsTotes, reduced to 11 All Post-free. On Approval. Send for List. New formula paper. WATKINS^ METER CO., Herefopd. HAND AND STAND FOR PLATES AND ROLL FILMS (DAYLIGHT LOADING) FITTED WITH BUSCH LENSES which means that you can work at twice and lliree tim'^s \he rapidity possible with tlie ordinary Camera on the market, B and so be mabled to take. PHOTOGRAPHS IN ALL WEATHER. Lists and Particniars of all Dealers or from THE BDSCH CAMERA Co., 31 Hatton f^ar Oct. 1899. — Its ar- rangements are simple and intelligible. The Lens defines well. I find Enlarging more interesting than any other branch of photo- graphic work I have tried. Burnley 9 Febr. 190O. — I have now had the opportuniiy of testing the ap- paratus for definition and equality of illu- mination through the range previously spe- cified. I am in every way satisfied with the results. In conclusion I wish to thank you for the prompt and concise replies to my queries. Send for ILLUSTRATED Price List. For Oil l..ight. For Klectric Ught. Designed and manufactured by WILLIAM HUME, 1 Loihian Street, EDINBURGH. I I CONTENTS. Chapter. Page. I. The Dark Room 1 II. Apparatus 6 III. The Lens 10 IV. Lens-Constants . . . . . . . . . 16 V. Testing and Choosing the Lens .... 21 VI. The Camera and its MovexAients .... 25 VII. Choice of Plates. Exposure 28 viii. Development . 31 IX. Development with Hydroquinone, Eikonogen, Metol, Amidol and Glycine ... 35 X. Duration of Development. .... 46 XI. Modifications of the Developer. ... 49 XII. Fixing, Clearing, Washing. .... 53 XIII. Intensification and Reduction . . 58 XIV. Varnishing Spotting Out, and Retouching Negatives . . • . . 63 XV. Printing on Albumenised Paper ... 69 XVI. GeLATINO- and COLLODfO-CHLORIDE PaPERS . 75 XVII. Plain or Salted Smooth and Rough Papers 82 XVIII. Platinotype Paper ... . .■ . 87 XIX. Bromide Paper . 95 . CONTENTS. Cliapter. Page. XX. Warm Tones on Bromide Paper and Alpha • Paper . . . 101 XXI. Carbon Printing. . o 106 XXII. Mounting Prints 116 XXIII. Lantern Slides . ^ 120 XKiv. Enlarging . 126 XXV. Portraiture ... ...... 132 ^fxvi. Architectural Work 138 xxvii. Copying . 141 xxMii. OrthochrOxAiatic or Isoctiromatic Plates: their Applications and Uses ... 147 xxix. Photography by Artificial and Flash Light 152 XXX. Pin-hole Photography. 157 xxxT. Stereoscopic Photography „ ^ . , . 160 xxxii. Hand or Detective Cameras ..... 173 xxxiiT. Instantaneous Work 179 XXXIV. Photography in natural Colours * „ . 182 XXXV. Iron and Uranium Printing . . . . , 187 XXXVI. The new Photography 192 xxxviT. Photo Freaks and other Photographic Tricks 196 XXXVIII. Failures AND Defects ....... 201 Appendix op Useeul Tables . ^ . 208 A PRACTICAL A B C OF PHOTOGRAPHY, CHAPTER I. The Dark Boom. PhotograpTiy as its name implies is tlie art or science of writing or delineating by the aid of light. Many are doubtless familiar with the old camera obscura to be found at many seaside places, where on a white surface the image of external objects is projected by a lens or glass placed in the roof. Were the. white surface of the camera obscura replaced by a sheet of glass coated with a mixture of gelatine and a chemical compound of silver, we should be able to obtain a photograph, that is, the silver salt would be so affected by light, that by treating it with certain solutions, we could obtain a negative, from which faithful reproductions in monochrome oould afterwards be obtained. A. negative is, or should be, the direct opposite of the natural object. Take, for example, a man in a black coat; in the negative his face, hands and collar would appear black, whiLt his coat would appear white orHransparent. From the above brief statement it is obvious that as light forms our negative or picture, it is impossible to manipulate the necessary sensitive surface except in a dark room. It is fortunate for us that it is not essential to have a room absolutely black; w^e can utilise a room lit by deep orange or red light with perfect safety. 2 ABCof Photography, If possible a room should be set apart entirely as a dark room and fitted with shelves, sink, waste-pipe and water supply. Failing this, a makeshift arrangement can be contrived which will answer our purpose admirably. A bath room, with which most modern houses are fitted, forms a very convenient dark room. To block out the light procure some strips of deal about one inch wide and three-eighths of an inch thick; of these make a framework to fit close on to the frame of the window, to which it may be fastened by turn-buckles top and bottom, or brass screws fitting into the window frame itself. Over this framework glue a piece of dark chocolate American cloth, on the shiny side of which is pasted one thickness of deep ruby paper. When this frame is made, fit it to the window, and closing the door, wait for a few minutes; then examine the window to see whether there are any stray gleams of white light creeping in through any cracks or crevices, if so, they must be stopped out with ruby paper. Instead of this framework, some red cloth, known to photo- graphic dealers, as *riiby fabric', may be obtained, and two thicknesses of this stretched on a small brass or iron rod over the window wnll effectually exclude white light. The panes of glass may themselves be pasted all over with starch paste, and ruby paper cut to the required size rubbed smoothly into contact. The disadvantage of this is that it is difficult to see in the room for ordinary household purposes, whereas the frame or curtains can be removed or drawn back, allowing the admission of white light when it is required. It is of course possible to use tlie red light obtained through the window, but I strongly recommend the purchase of a dark- room lamp. The light is more constant, an important factor in photography, and it is with a lamp possible to work in the evenings and at night when daylight is no longer available. The lamp should be of fair size, and should burn paraffin. Never purchase a candle lamp. The oil-reservoir should be entirely separate from the lamp chamber itself; this obviates any heating of the paraffin and consequent smoking and small explosions. If there is a gas supply in the room it will be extremely easy The Dark Room. 3 to fit a temporary T piece on the ordinary burner, and from this to lead an india-rubber pipe to a gas-lamp. Tbe glass of many lamps is extremely unsatisfactory, and it will be found not only far pleasanter to work with, but also much safer for the plates, if a piece of flashed ruby glass ground on one side be placed behind a sheet of deep orange glass. Never use paper, or cloth, in a lamp, it always gets dirty and smoked, and too often catches fire at a critical moment. A sink with waste-pipe is an essential, unless of course the bath itself be used as a sink; in the latter case it is advisable to have a few wooden slats nailed together to fit over the top of the bath to form a shelf for the dishes etc., to rest on. A wooden sink lined with lead is a great convenience, but a well-made box, such as an empty champagne case can be pressed into service. To make the sink out of a champagne rase; have a hole cut in one corner, for the waste-pipe, the end of which should be passed through, and then the edges flattened, turned down, and nailed with large-headed copper nails. Unless one is handy with tools it is advisable to get a jobbing carpenter and plumber to undertake this work. If there are any large cracks or crevices in the box it should be rejected, and the joints should be well filled up with cobbler's- wax or ordinary yellow bee's-wax or putty. The whole of the interior should then be given a coating of The first coat must be left for one day ta thoroughly dry, and then a second should be applied. This solution will reader almost if not every wood water-tight; the only precaution to observe is not to use it near any light, or else the vapour may explode. Failing a water supply, I should strongly advise the purchase of one of the portable galvanised iron cisterns, which can be hung on nails to the wall and filled before starting work. The other outfit for the dark room should consist of four measures: one minim measure ranging from 1 to 120, oQe2oz. -measure, cylindrical in shape for preference, one 4 oz. measure Asphalt Mineral naphtha India-rubber . . . 4 ozs. 10 ozs. 30 grs. 4 A B C of Photography, and one 20 oz. measure, with also an earthenware jug graduated inside up to a quart. Three dishes must at least be obtained, and half a dozen is far better. The ordinary dishes are either glass, ebonite, celluloid, or earthenware; and of these, the last are, though heavier, decidedly preferable, particularly the. deep ones. To contain the fixing solution, better far than an open flat dish is the deep-grooved trough, it takes up less room and the solution keeps cleaner and fit for use longer. Of course some shelves should be fitted up to take the bottles, dishes, small accessories, and chemicals, a list of which can easily be made up to suit the particular work which it, is intended to do. At first the beginner will, like many old hands even, think it absolutely necessary to place his lamp right in front of him and just above his dish in which he develops the plate; this, however, is the wrong way to work. Although it may practically be considered that the ordinary photographic plate is not sensi- tive, that is, will not be affected by the red or orange light of the dark room, this is only relatively true -for give it time, and any red light will affect the plate. It is therefore better to turn the lamp so that the back of it is towards the dish, and so that the light shines on to the whitewashed wall, or a piece of white card, and is thence reflected to the dish, This method of working is not only safer for the plate, but more pleasant to the eyes. For extremely sensitive and the orthochromatic or colour-sen- sitive plates a much deeper light is required, and this can be obtained by using one sheet of deep cobalt blue glass and one thickness of deep ruby. The combination of the two gives a light which is very safe, but which has not any great illumin- ating power. This, however, will be treated of later on. Ventilation in a dark room is one of those points too of- ten neglected by photographers, but to work for some time in a small room with a lamp burning and frequently also with a pipe smoking, the air becomes extremely fetid and unplea- sant, causing headache and lassitude. Ventilation may easily be secured by cutting a row of holes in the bottom of the door. The Dark Room. 5 eacli about half an incli in diameter, and nailing over them inside a piece of wood projecting out at an angle of 45°, and opening the window at the top for an inch. Very convenient portable dark rooms can be purchased ready made from one guinea, and one of these can be placed in a yard, or garden, or even in an ordinary' bedroom, without being very unsightly. Makeshift arrangements of all kinds can be contrived from a second-hand servant's washstand, which may be bought for a couple of shillings, and I have before now worked with such an arrangement, light being excluded by curtains made of black twill lined with yellow. CHAPTER II. Apparatus, Several points have to be taken into consideration when 2)urchasing apparatus, and to the beginner I would. strongly urge the necessity of obtaining, if possible, the advice of an expert, not that of a mere beginner. Second-hand apparatus as a rule is unsatisfactory, and the purchaser wants to be thoroughly wide awake to know whether he is getting value for his money or not. The seller of second- hand apparatus does not mean to be intentionally dishonest, he merely puts as high a price on his battered goods as he can and naturally does not point out the defects which have developed by constant use. Complete sets of apparatus too are temptingly offered by dealers, but it is better to purchase the articles separately. The various sizes of sensitive plates are made in certain sizes as follows: 31/4 X 31/4 inches or lantern size. 41/4 X 35/4 „ „ quarter plate. 5X4 ) 6I/2 X 43/4 „ half plate. 6^/4 X 31/4- „ „ stereoscopic size. 71/4 X 41/2 „ 71/2 X 5 8X5 8I/2 X 6I/2 whole plate. Apparatus. 7 9X7 inches 10 X 8 12 X 10 15 X 12 The quarter, half and whole plate are the usual sizes. For touring, especially for ladies, I strongly recommend the quarter plate, it is light, will pack away into a small space, and gives negatives from which lantern slides can he easily made and which can also he enlarged to make larger pictures. The half plate is a good size, it is convenient for stereoscopic work, and the prints are not too small to hang on the wall; the whole is too heavy for touring, hut the prints are more imposing- looking. It must not he forgotten that the prime cost of the apparatus is hy no means all that will have to 'be incurred — plates, dishes, printing- frames and paper, the first and last of which are constantly recurring items, increase by more than double in the half plate as compared with the quarter, and in the whole as compai*ed with the half plate. At the present time there is a far greater tendency to work small sizes than large, which are not essential to turn out artistic work. There are two distinct types of camera, the one shown in Fig. 1, with conical or tapering bellows, and the other shown in rig. 2, with square bellows. It will noted that in Fig. 1 the back is fixed, whilst the front is movable, whereas in Fig. 2 the reverse is the case. The construction of Fig. 1 allows of a slight reduction of weight, and provided the bellows do not taper too much, there is no objec- tion but too often in sacrificing everything to obtain lightness, manufacturers make the bellows so tapering as to make the camera useless for many kinds of practical work. Personally, I have a great predilection for the square-bellows camera, and no matter what sized camera I wanted I should choose this in prefer- ence to the other. The particular parts of a camera and its various movements will be described in detail hereafter, but without troubling to enter into elaborate explanations, I may point out that the essentials 8 A B C of Photography of a good camera are firmness and rigidity when extended, a rising and falling front, a reversing and a swing back. These must be included. There are other minor improvements and Fig. 1. additions which may be looked for, and the description of these will be found later on. Fig. 2 Besides the camera proper it is necessary to have what are Appaj^aius. 9 known as double backs or dark slides, which are thin, flat, wooden boxes to hold the sensitive plates. The tripod stand, or legs, are fairly well known even to the uninitiated, but it is just as well to point out that they should be as tall as possible considering the height of the operator; to have to stoop down to a four-foot stand when one is over six feet in one's boots is trying to both the back and temper. In choosing a stand, have it set up, and place the hand firmly on the tripod- head or top, which is always triangular in shape, and try and twist it from side to side. If the legs twist with the hand reject it, if on the other hand it withstands any attempt at twisting it will be satisfactory, and we can pass on to the next test, which is to hit the top firmly with the flat of the hand three or four times, if there is much shaking or vibration then reject it, because it will shake and vibrate in use. If the stand has passed successfully through these two tests have the camera screwed into it, and then see whether the whole is rigid and free from vibration and shaking, if so you can accept it. Frequently a stand is all right by itself, but when the camera is put into it it will not stand much. Tripods are usually made in two, three, or four sections. For large cameras the two-fold stand should be chosen; for small cameras the three or four- fold stand should be adopted; it is immaterial which form as long as it is firm, rigid, easily set up and taken down, and has a large head or top ; many tripod heads are far too small, and they should always be covered with leather. Personally, I prefer a wooden head covered with cloth. It can be made larger and therefore firmer, and does not scratch and score the baseboard of the camera. Whatever form of stand is adopted the bottom fold or leg should slide, this enables one to adjust the stand to uneven ground, which in practical work will be found extremely convenient. C FI A P T E R IT T. The Lens. This is certainly the most important of all the apparatus \vhich Fig. 3. a photographer must possess, we shall therefore consider it at some length. The Lens. There are three main types of lenses. The portrait lens shown in Fig. 3. The rapid rectilinear or doublet Fig. 4. And the single or landscape lens, Pig. 5. The portrait lens is of little use to the amateur, it is extremely expensive, very heavy, and can practically only be used for por- traiture. It may, when experience has been gained, be added to the stock of apparatus, but it is decidedly unnecessary when starting. The rapid rectilinear, which is known by all sorts of names, is the most useful lens for all round work. With it portraits, AB C of Photography. landscapes, arcWtectare (exterior and interior), may be success- fully coped with, as well as copying from pictures or black and white work. The sint^le landscape or achromatic meniscus is cheaper than Lhe rectilinear, but is suitable mainly, as its name implies, for Fig. 5. landscape work, though it may be used for portraits, architecture and copying under certain conditions. In choosing a lens certain important factors have to be taken into consideration, which can be best explained by taking them seriatim, which we shall proceed to do presently. A lens is composed of different parts, which will be best grasped from an examination of the accompanying figure Fig.4 shows the lens complete, and Fig. 6 dissected to show its several parts. 1 is the flange which is screwed on to the camera front, and into which the body, tube, or barrel of the lens itself screws ; II. is called the back combination, and, as will be seen later on, may consist of one, two or more pieces of glass of particular shape cemented together so as to look like one piece; III. is the front combination; IV. is the barrel or tube; V. the hood, a piece of brass which protects the lens from damage when covered with VI., the cap, which is usually made of leather; VII. is a slit or slot into which pieces of brass, shaped as shown in Fig. 7 are inserted. The Lens. 13 These are called Waterhouse stops. The use of these will be explained later on, The stops or dia- phragms may also take the form of a revolving wheel, when they are called wheel diaphragms, Fig. 8, or they may take the form shown in Fig. 9, when they are known as iris diaphragms, and are quite enclos- ed in the tube, and are actuated by an external pin or knob. With a single or landscape lens, as Avill be seen from Fig. 5, only one combination is used, but the same terms apply to the several parts of the lens as a whole as just described. The lens is one of the most expensive parts of the outfit, and therefore great care should be taken of it. It is a good plan to buy a second cap, which should be A B C of FJ;Otography, fitted on the back combination of tbe lens, and wbicb will tbus protect the latter from injury. A wash- leather bag may also be made large enough to contain the lens, the bottom of the bag being made of a piece of thin wood or stout millboard. The glasses will occasionally get dirty, in which case they should be carefully and gently wiped with an old soft silk handkerchief or piece of soft, clean wash-leather. They should never be washed or rubbed with the fingers. It is always as well to see that the lens is clean and free from dust before com- mencing work, as a dirty and dusty lens is frequently the cause of flat and foggy negatives. Fig. 7. If Waterhouse stops are used, they are sometimes liable to get lost, to prevent which a small brass rivet may be fastened through the tongue or projecting piece, which will hold them together. Frequently too, they get worn bright, and to reblack them the following method may be used. In a gallipot place about 2 ounces of strong nitric acid, and then add sheet copper, or copper wire and allow to stand. This must be done out of doors, and enough copper should be added till the acid will no longer dissolve any more. The resulting solution should be a deep greenish colour. The stop to be blackened should be first cleaned wdth fine emery paper till it is bright everywhere, The Lens. 15 and should then be well washed in strong ammouia and water, then in plain water, and finally hung on a piece of wire or string, and dipped into the solution and then heated over a spiiit or gas stove till it darkens. This operation should he repeated till it is quite black, and it should then be wiped with a dry cloth, and brushed over with any plain varnish and allowed to dry. The interior of the lens tubes may be reblacked by mixing a little gold size, tur- pentine and lampblack to a stiff paste which can be applied with a brush. If it is found necessary to Pig. 9. take a lens to pieces to clean it, great care should be exercised not to displace the combination, and it is as well to clean one combination and replace it before unscrewing another. In the case of a portrait lens it is important too, in the back combination, which lens and even which side of the lens is next the ground glass, but careful noting how these lenses are placed, and by reference to Fig. 3 no difficulty will be found in this respect. CHAPTER IV. Lens-Constants. If we use a magnifying glass to examine any object we shall find that there is a certain distance from the object at which it appears distinct or, as photographers call it, sharply defined. This distance is called the focus. It is usual to speak of the focus of a photographic lens as the equivalent focus or focal length. And the former is derived from the fact that it is compared to the focus of a spectacle lens of very great thinness. As we shall have to mention and use the equivalent focus several times, we will at once proceed to state how to determine this. Fix the camera up on its stand; against the wall of a room pin a foot rule. On the ground glass of the camera mark off with lead pencil three inches; now shift the camera nearer to or further from the foot rule till its image just falls within the lead pencil marks on your ground glass, then measure the distance between the ground glass and the foot rule, this gives us the first factor. Now divide the size of the foot rule by the size of its image, this gives us the second factor. To explain the further steps we will take an actual example. — We want to find the focus of a lens, and proceeding as above, we find the distance between the foot rule and ground glass to be fifty inches: the proportion of image to object or the ^ foot rule divided by the marks on the focussing screen is ob- viously 12 -f- 3 z= 4. Lens- Co list ants. 17 Then we proceed as follows : — we multiply the distance by the proportion of image to object 50 X 4 200, This amount we divide by the proportion of image to object, plus one, squared : — thus, 200 -f [(4 + 1) X (4 + 1)] == 200 -f- 5 X 5 = 200 ~ 25 = 8 inches which is the equivalent focus or focal length of the lens in question. The next constant to determine is what is called the rapidity of a lens, that is to say, assumiug everything elss to be con- stant, what amount of light it allows to pass; for on the amount of light depends to a great extent the duration of expo- sure, and therefrom the success of our work. The rapidity of a lens is usually expressed as the ratio aperture, that is, the ratio which the aperture of the lens bears to the equivalent focus. Prom the equivalent focus we can determine the ratio aperture of the stops. We have found by a simple calculation above, that the focus of a lens is 8 inches. We now measure the diameter of the aperture in the largest stop, and we find this to be 1 incb, then 8-^1 = 8, the ratio aperture of that diaphragm which is usually written f/8 or F/8. The next stop measure I/2 inch, so 8 -f- 1/2 = ^l^^- Thus we proceed with all the stops and we find that as a rule those usually provided with rectilinear lenses are F/8, ll Sl, 16, 22'62, 32, 45 and 64. With single lenses the series usually starts with F/1 1-31 as the largest. With portrait lenses it is F/4, F/6 F/8 and soon. Now to explain the use of stops. When we set our camera up and focus the wall of a room or house, we shall find that probably only the central portion of our screen is sharp, that is, that here only can we see the pattern of the wall-paper or the bricks distinctly, but as we proceed to the edges the image gets blurred and indistinct. If now we insert a stop we shall find that the sharpness- extends still further, but that the screen i8 A B C of Photography, is darker, and by insertins; the stops in turn we sliall find one that will give us crisp sharpness or definition, all over the screen, but the light is now considerably dimmed. We have established therefore one fact, and that is, that stops or diaphragms are used to obtain better definition towards the margins of the focussing screen. There has been, however, considerable diminution of brightness; this we shall now proceed to examine. It is a fact, which does not need much explanation, that through a given sized hole you can only pass a given amount of light, the quaestion is how much light do the stops pass. This can be found by squaring their numbers thus : 8 X 8 64 11-31 X 11'3L 128 (in round numbers) 16 X 16 256 22-62 X 22-62 5T2 ( „ „ „ ) 32 X 22 1024 45-25 X 45-25 2043 64 X 64 4096 If we assume now that !P/8 or 64 is the greatest amount of light, we shall find the numbers run thus, 1, 2, 4, 8, 16 32, 64, and as we know these are in inverse ratio, that is to say, F/11 is smaller than r/8, we find that the amount of light transmitted by eaeh stop is 1, l/.2» V4' "^^8» Vl6' V32» V64- Now suppose a subject with a given lens, working at F/8, for this is the usual method of expressing it, required 4 sees, and we wanted to use a smaller slop to obtain greater sharpness, let us say r/22 we merely have to remember that this latter passes one-eighth the amount of light and therefore to obtain the same effect we must give eight times the exposure, so that the ratio aperture squared will give us the relative exposures with any given stops no matter what the focus of the lens may be, because the ratio apertures of the stops bear absolutely the same ratio to one another, and if the focus is longer, of course the diameter of the diaphragm aperture will be larger. If, on the other hand, the focus is shortened, the aperture is diminished. Lcns-CoJistants . 19 It was stated ia Chapter III. that single lenses could be used for architectural work under certain conditions. It is an un- fortunate fact that single lenses distort the imagCj that is, straight lines near the margin of the focussing screen instead of being Fig. straight appear curved. It is for this reason that single lenses should not be used for architecture. It must be admitted how- ever, that rarely in ordinary work does this make its appearance, and I have for years used single lenses for architectural work, but this is not a practice which should be followed by beginners. 20 A B C of Photography. In all catalogues will be found lenses described as narrow- angle, mid-angle and w^ide-angle. The width of angle included by a lens means the amount of subject w^hich is included by a lens on a given sized plate, and a lens is only of narrow, mid or wide augle when used on one particular plate as wqll be seen from the followiug Figure 10. Let L represeut a lens, and I. be a quaiter plate, the amount of subject included is not much and for this plate the lens L would be of narrow angle. Let IL represent a half plate, on this the lens would include a mid angle; and let IIL represent a whole plate on which the lens would include a wide angle. Wide-angle lenses are useful for taking architectural subjects in narrow confined situations, where it is impossible from the nature of the surroundings to get far away from the building. They should be used as sparingly as possible as they give an exaggerated or distorted perspective, that is to say, they make uear objects look much larger than those further off. CHAPTER V. Testing and Choosing the L^ns. There are certain defects to which most lenses are liable, and we will proceed to consider how to test for the same. The covering power of the lens is its ability to define sharply on the ground glass, objects which are before it; it may be determined by setting the camera up opposite a row of houses, focussing the centre of the screen sharply, and then measuring the extent of shai'ply defined focus from the centre of the screen with a foot rule, carrying this procedure out with each slop. * Flare' is a central bright spot of light seen on the centre of the ground glass, and it is extremely annoying and difficult to cure, and spoils every negative. It should therefore always be carefully looked for. Set up the camera at night, and about four feet from it, in front of a dark curtain, place a lighted candle, and focus the flame sharply on the ground glass. The image of the flame will be seen to be surrounded with a bright halo. Now slightly unscrew the camera and swing it round on the top about two inches, if the ha^.o or ring of light remains steady in the centre of the field and does not move with or in the opposite direction to the camera, it is ' flare', and the lens should be rejected. There are other defects to which the lens is liable, such as spherical aberration, non- centreing, imperfect polishing etc., but the tests for these are extremely difficult to carry out, and I think it as well therefore to omit them. The first thmg to do in choosing a lens is to decide v:^hether ABCof Photography, It is to be rectilinear or single. If what has been said before is borne in mind no difficult! will be experienced. The second point is the quaestion of length of focus, we bave already seen that short focus or wide-angle lenses give exaggerated perspective, and the best proportion of focus to the plate is one-third longer than the longest side; for instance, for a quarter plate it will be 4^/4 + 1/3 (41/4) = 6 inches, practically. Several types of rectilinear lenses are on the market: there is one called a Euryscope. This is practically the same form as the ordinary rectilinear, but works at F/6 and is therefore practically nearly twice as quick. They are good lenses suitable for portraiture at full aperture, that is, when used without a stop, and when stopped down will do all that the rectilinear will. The construction of newer types of lenses with larger apertures and greater covering power has considerably advanced of late, and Fig. 11. it is now possible to obtain lenses which work at r/4 and r/5-6 which will cover given sized plates better at those apertures than some of the older lenses will at F/S or F/11, etc. These lenses are of course rather expensive, but as they may by describfcd as universal lenses suitable for every class of work, inclusive of Tesii/ig and Choosing the Lens. 23 the fastest instantaneous shots, portraiture, etc., they will in the <'nd be found b)^ no means so expensive as their price would at iirst warrant one in assuming. 'J'o this class of lenses belong Dallmeyer's Stigmatio, Zriss Prolar, Unar and Plauar, Goerz Anastigmats, Beck Steinheil Osthostigmat and the Voiglitlander Coliinear, as well as the newer Kapid Symmetrical Anastigmats of Ross. One of our English firms, too, Messrs. Taylor and Hohson, of Leicester, have introduced a new form of lens which differs from the rectilinear in having three glasses, two outside and one in between, as shown in Fig. 11. This is a great advance, and for the same focus and aperture posesses very great covering power, and works at an aperture of F/6.5. It frequently happens that in landscape work we find when the camera is set up and the view focussed that objects are extremely small. It should be remembered that the nearer we .ire to an object the lariier its image, therefore it may be possible to shift the camera bodily nearer and so obtain a larger image. But suppose that it is impossible to get any nearer, what are we to do? If we have several lenses then we should use that with the longest focus because the size of an image is — all other things, such as tiie distance of object and camera being the same — in direct proportion to the focus of the lens. Thus if a 4-inch focus lens gives us an image of a certain house 1 inch in height, an eight-inch lens will give an image two inches, and a twelve- inch an image three inches in height. Whilst the image of an object is in direct proportion to the size of the lens, and we can by using long focus lenses obtain much larger images of distant objects, it will be found extremely inconvenient as a rule, and actually impossible in many cases, to use a lens of very long focus, not only because our cameras are not built with extiemely long bellows but also because if they were the chances of vibration from the same would be very great, and therefore opticians have provided us with what are known as telephoto lenses, that is, a supplementary negative or concave lens which can be screwed on behind our ordinary lens, which enables us to obtain very much enlarged images of distant 24 A B C of Photography, objects without undue extensioa of the bellows. lu fact by the aid of these telephoto lenses it is possible to obtain photographs of objects at a distance of 3 or 4 miles, and they will be as sharp and clear as though we were only within a few yards of these objects. Assuming, however, as frequently happens, that we have only one lens, if this happens to be a rectilinear we can unscrew one of the combinations, either the front or back, and we shall im- mediately have a single lens of double the focus, which will give us an image just double the size. It must not be forgotten that when thus doubling the focus, the aperture oi the diaphragm remains the same, and therefore its ratio aperture is halved and the exposure increased fourfold, not doubled only. There are several other points in connection with the lens which we shall come across as we proceed to various branches of w^ork. CHAPTER VI. The Camera and its Movements. Before taking a camera out to work it is just as well to thoroughly familiarise oneself with all its working par(s, fintl- iog out the whys and wherefores of each separate movement and thus be in a better position to make use of them in practice. First of all, set up the tripod, screw the camera on to the head, and open it. Screw the lens into place and focus the wall of your room, or if you have a back window overlooking a row of houses, throw the window open and placing the cam- era just inside, proceed to work. There is a right and a wrong way to do everything. Place your tripod with one leg right in front of you, the other two being on each side, so that you can comfortably stand between them. Now take hold of the front leg and move it nearer to or farther from you, you will at once see the effect is to include more or less foreground. Proceed in the same way with the right and left legs and you will find that by thus figuring about you will be able to so arrange the image of the houses opposite that they do not look as though they were tumbling backwards, or were all running up or down hill. The straight lines in any object must be parallel to the straight edge of your focussing screen, if they are not, they will be crooked in the resulting print. Having thus managed to arrange your camera level and up- right, try the effect of the rising and falling front to which 26 A B C of Photography. the lens is attached. Moving this up will, it is found, exclude more foreground and include more sky, frequently a valuable dodge. Now supposing we are not using the camera level, but have pointed it up, as shown in Fig. 12, if we take a picture Fig. 12. with the camera in this position we shall find thai^ any parallel lines will converge, so to correct this we use the swing back, that is, we unscrew the brass heads and shift the back till it is perfectly horizontal, as shown in the Figure 12; this will keep the lines parallel. It will be found on careful examination that the framework carrying the ground glass can be unshipped; this forms what is called the reversing back, and its use is to enable one to alter the longer axis of the picture from the horizontal to the vertical and vice versa. Each separate motion of the camera should be studied and gone through several times, till one is perfectly conversant with the same. It saves a lot of time and trouble afterwards. To focus, after having screwed the lens into position, cover the back of the camera over with the focussing cloth, and under The Camera and its Movements. 27 tliis place the head, gathering the cloth up under the chin with one hand, so as to exclude as much light as possible. Now with the other hand work the screw or rack and pinion, which will be usually found attached to the side of the baseboard, till the image appears fairly sharp. This can best be seen by keeping the face about six inches from the glass. Then as soon as it is as sharp as it is possible to obtain it in the centre, insert the stops in rotation till it is sharp all over. Some cameras instead of having a solid base-board have the latter cut away in the centre, and the brass pins on to which the legs fit are let into the base-board, and on the metal ring carrying these the camera may be shifted; this is called a turn- table — it lessens the weight of the camera slightly and is conve- nient in many ways, and for small cameras has no disadvantages. Por larger cameras, however, it is doubtful as it may prove to be a source of weakness. CHAPTER V 1 1. Choice of Plates. Exposure. Tlie plate, or dry plate, as it is usually called, is a sheet of glass of a certain size coated evenly with a mixture usually called aa emulsion of silver bromide in gelatine : this mixture is extremely sensitive to light, and therefore a packet of plates must only be opened in the dark room. Dry plates of excellent manufacture can now be obtained in almost every town of any size, and in various rapidities, slow or ordinary, rapid and extreme rnpidity. The first are most suitable for landscape and architectural work; the rapid for portraiture, and the extreme rapidity for instantaneous work. 1 should strongly advise the beginner to adhere at first to the ordinary, they are much easier to work and, as a rule, will give him far more successful results; as he obtains a belter grasp of the subject it will be time enough to try the more rapid ones. The plates are carried in the dark slides, and to fill these go into the dark room, open the slide, lay it On a bench or table, open the box of plates and unwrap one of the small packets. Most of the manufacturers pack their plates film to film, so that in opening a packet there need be no difficulty in tclliug which is the right side; although this is by no means a difficult matter, for the shiny, polished surface of the glass will not hold the nail, w^hereas the gelatine drags readily when touched w ith the nail. The coated side should be placed down- wards as the dark slide lies open in front of you, that is, the uncoated sides must be back to back when the slide is closed. Choice of Plates, Exposure, 29 but should of course be separated by a piece of black card or metal to prevent the light striking through from one plate to the other. When the slide or slides are filled, and in doing this be careful to expose the plates to the light as little as possible, close them, shut up the box of plates, and you are ready to return to the light of day. On correct exposure depends to a great extent the success which will be attained, and although it is one of the most difficult problems to solve in connection with j)hotography, there are several valuable helps in the shape of exposure meters, and also some e.^posare tables, of the latter one can only say that they are better than nothing, and of the former they really are of considerable assistance to the beginner and even to the old hands. One which I have used with very satisfactory results is known as VVatkin's Exposure Meter, which is sold in three forms. The principle on which this is founded is a sound one: a small strip of sensitive paper is exposed to a light which is equal in brightness to a shadow of the subject to be taken; if necessary even in an tctual shadow itself. The time the paper takes to darken to a standard tint is counted by means of a small chain fastened to one end of the meter, this forms a pendulum beating half seconds. The time having been noted, the various pointers are set to the numbers they correspond to, whilst the final pointer is found opposite the required exposure. Full instructions for using the instrument will be found sent out with it, as will also a table giving the different speeds of the various commercial brands of plates. Before starting to work in an open public place it is advisable to test the instrument and all your methods of procedure, by making an actual exposure on your back garden or the view from your frolit or back windows— and I will assume that you have determined to do this, and we will together run over once again the necessary operations. Remember that method in pho- tography will lead to considerable reduction of the number of failures. Set up the stand, and screw the camera into position. Open it, and screw the lens into its flange; remove the cap, placing 30 A B C of Photo g7'apJiy , it for tlie time being eitlier always in one place, such as on the top of the bellows, or preferably into your pocket. Throw over the camera the focussing cloth, insert the head under the same, and focus the view, insert the stops till it is sufficiently sharp. Tarn back the focussing cloth, put the cap on your lens, turn back the focussing screen, and insert the dark slide in the grooves, whence the ground glass has just been removed, in doing this be careful not to shift the camera. Now calculate your exposure, draw out the sliding shutter of the dark slide — do this gently and be quite sure you draw out the right one, the slide should be turned back, covered with the focussing cloth, and the cap gently removed, the necessary exposure given and the cap replaced, Practice well taking off and putting on the cap so as not to shake the camera; the sliding shutter of the dark slide shonld be pushed back again, and the exposure made a note of, with the conditions as to light, time of day, subject, etc., in one of the many little books provided for that purpose. Be careful to note what was the number of the slide you exposed; in fact, at first it is just as well to carry about with one small strips of gummed paper, such as stamp-edging, a piece of which should be stuck over the slide after exposure, so that it cannot be again withdrawn. If this is done and a note made as to the number, etc., of the exposure, all danger will be obviated of what is known as a double exposure, which means that you will not obtain a negative showing a ghostly cow or landscape combined with a beautiful example of Norman architecture, or the portrait of a young lady half in and half out of a muddy pool fringed with willows; incongruities and mistakes to which even the most expert of us are at times liable. CHAPTER VIII. Development. It has been said that photography is easy enough till you come to development, and then it becomes a science._ Another old chestnut is that a well-known worker when asked how he devel- oped, replied: "With brains/' and there is a good deal in that remark. Although by giving precise directions it is possible to assist the beginners a great deal, by pointing out possible failures, or chances of failures, yet the directioDS must be used intelligently or with brains. The usual developers are ferrous oxalate, pyrogallic acid, also called pyrogallol or pyro, hydroquinone, eikonogen, metol, amidol and glycine. Ferrous oxalate has now almost, if not entirely, gone out of use for negative work, I shall not therefore give directions for using it, and in giviug directions for the use of the other developers I shall merely include formula3 and methods which I myself have well tried in practice. The constituents of a developer are the developing agents proper, a list of which I have given above ; a preservative, which is usually added to keep the solution clear and bright, sodium sulphite and potash mxctabisulphite are generally employed for this purpose; a restrainer, which is potassium bromide, and which makes development slower, and an accelerator, which is usually an alkali, such as ammonia, or the carbonates of potassium and sodium. The purpose of the accelerator is to hasten the development. 32 A B C of Photography . Pyro is a wliile featliery substance which very soon turns black wheo exposed to the air, it is therefore advisable to make up a solution and keep it in a well-stoppered bottle. The following is a good formula which will keep for months without turning dark : Pyro 1 oz. Potassium metabisulphite 1 oz. Distilled or boiled water to make .... 9 ozs. Place the metabisulphite in a half-pint measure, add about 6 ozs. of water to it, and stir with a glass rod till all has dis- solved: then open your bottle of pyro, pour the solution into it, stir once or twice and return to the measure and make the total bulk of solution measvire 9 ozs. by rinsing out the pyro bottle with water and adding to the measure. Immediately transfer to a bottle and cork or stopper it, and label it, "Pyro Solution 10 per cent." Ten per cent, means that every ten minims contain 1 grain of pyro. For the restrainer use Potassium bromide 1 oz. "Water to make 9 ozs. Dissolve by stirring, bottle, and label " Potassium Bromide 10 per cent." This may be used for every kind of developer. For the accelerator we may use either ammonia, potash, or soda; of the three soda is preferable for beginners, but I will give formulse for all three: — Ammonia Accelerator Strongest solution of ammonia 1 oz. Distilled or boiled water 9 ozs. Label "Ammonia 10 per cent." Be careful in measuring this as the fumes are very pungent and irritating. Potash Accelerator Potassium carbonate 1 oz. Distilled or boiled water to 9 ozs. Label "Potash Accelerator 10 per cent." Development, 33 Soda Accelerator Washing soda 1 oz. Boiled or distilled water to 9 ozs. Label "Soda Accelerator 10 per cent." The normal quantities of these solutions to use for evq^-y ounce of developer is Pyro solution 20 minims. Bromide „ 10 „ Ammonia,, 20 „ or Potash „ 100 or Soda „ 140 „ , The ingredients should be measured out with a small minim measure, poured into a two ounce measure, or a teacup without a handle may be used, and then flowed over the plate. We will now proceed to the actual development. Take a dish of the proper size and see that it is clean, have your developer ready in the measure. Open the dark slide and place the plate film upwards in the dish, taking care to shield it as much as possible from the light. Then lift the dish with the left hand, and hold it slio-htly slanting from you ; take up the developer with the right, low^er the measure to the dish at one end and quickly and evenly draw the mea-sure from left to right, and thus flow the developer over the plate, and immediately rock backwm'ds and forwards, putting the measure down so as to have both hands at liberty. It is now time to look out for air bubbles, or air bells as they are frequently called, and they adhere very tenaciously to the gelatine, particularly in hot weather. They can always be seen by holding the dish rather high and gently rocking it, when any air bubble will form a little wave in the developer as it flows over the plate. The usual method of breaking them with old workers is wdth a finger, it is rather a dirty habit — dirty for the fingers, I mean, because pyro stains them ; but for those who do not like to use their fingers a broad soft camel-hair brush, about two inches broad, should be bought, and this passed very gently over the plate, then well rinsed and hung up to dry. 34 AB C of Photography. Although these operations have taken some time to describe, they should not take more than forty or sixty seconds to carry out. and practice will soon enable the beginner to carry them ont neatly and quickly. .When the plate is placed in the dish, absolutely no trace of any picture can be seen on it, but it will not be long in the developer before it will be seen that the film will begin to darken in parts; if it is a landscape the sky will begin to show up dark, if a portrait then the face and hands or collar and culls, these are called the '•high lights' of the picture. Gradually we shall see the darker portions, such as the trees or grass, in the landscape showing, these are called ' the half tones.' Some- times it happens, that from over-exposure the whole image flashes up at once, then the only thing to do is to immediately fill the dish with water, wash the plate and apply a developer with about 4 times the quantity of pyro and bromide but with about one-fourth of the accelerator, and continue development till the plate is absolutely black all over, and then wash and fix. Sometimes loo the high lights are a very long time before they appear, and, when they have appeared, with only a few of the brighter half tones, the shadow or rest of the plate remains nearly white, in such a case fill the dish up with water, add some more accelerator and leave it for tea or twenty minutes, this would be a case of severe under-exposure and but little can be actually done to save such a plate. Upon the duration of develo])ment to a great extent depends the beauty of the results, and it requires an enormous amount of experience to tell exactly when to stop development; but fortunately for baginners, there is one very simple method which facilitates matters a great deal, and this will be explained later on. (See p. 46.) CHAPTER IX. Development with Hydroquinone, Eikonogen, Metol, Amidol and Glycine. Hydroquinone had for some time a very liigli place in the favour of amateurs, but latterly it has been ousted by the other newer developers, which are at the head of this chapter. It is a clean- working developer which gives pretty-looking negatives, but is not so good as pyro, nor as the other developers. The following formulae will give good results: No. 1. Hydro qui none 154 grs. Sodium sulphite • 2 ozs. Sulphurous acid 07, Distilled or ioiled water to make ... 10 ozs. No. 2. Washing soda 1300 grs. Caustic potash * 134 grs. Distilled or boiled water to make.. 10 ozs. For use, mix an ounce of each and add three ounces of water. As described for pyro, half the quantity of No. 2 solution may be used at first; the same quantity of potassium bromide being added to every ounce of the mixed developer, as recommended for pyro. Eikouogen has not such a good name as hydroquinone ; it acts quicker, but has one defect, that of not giving sufficient 36 A B C of Photography. density and a tendency to fog, terms which will be explained hereafter. No. 1. Solution. Sodium sulphite 2 ozs. Dissolve in 10 ozs. of water and adi Hydrochloric acid 1 dracLm. Then add Eikonogen 125 grs. Sufficient water to make 25 ozs. No. 2. Solution. Washing soda 21/2 ozs. Caustic potash 125 grs. Distilled water to make 25 ozs. For use, mix in equal parts, and add restrainer in the same proportion as for pyro. Metol, one of the newest developers, is certainly well deserving of attention by all. Personally I do not advise its use alone, though I give a formula for it I strongly advise the combination of metol and hydroquinone, or metol and pyro, and the latter for preference. No. 1. Solution. Potassiun» metabisulphite 1 oz. Metol 160 grs. Distilled or boiled water to make... 10 ozs. Dissolve the metol and then add the metabisulphite. No. 2. Solution. Potassium carbonate. ll/g oz. Distilled or boiled water to 10 ozs. Mix half an ounce of Nos. 1 and 2, and add 21/2 ozs, of water and the restrainer as for pyro. Metol-Pyro Developer. No. 1. Solution. Pyro 55 grs. Metol 45 „ Development ivith Hydroquinone, etc. 37 Potassium metnbisulpliite 120 grs. Potassium bromide 15 „ Distilled or boiled water to make ... 20 ozs. No. 2. Solution. Washing soda 2 ozs. Distilled or boiled water to 20 „ Mix in equal parts for use. Metol and Hydroquinone Developer. Use exactly the same formula as the last, only replace pyio by hydroquinone. Glycine Developer. No. 1. Glycine 300 grs. Sodium sulphite 2I/2 ozs. Distilled or boiled water to 10 „ No. 2. Potassium Carbonate 1 oz. Distilled or boiled water 4 ozs. l^r use mix half an ounce of No. 1, quarter of an ounce of No. 2, and three ounces of water. The restrainer as for pyro. For ladies and those to whom soiled fingers are a consideration, I would advise the use of hydroquinone, or hydroquinone and metol, or glycine. As each year passes, we find introductions in the shape of new developers, most of which are heralded with a big flourish of trumpets, but practice does not always prove that the newcomers are better than, in some cases indeed equal to, the old favourites; still to makes this chapter more complete the newer developers have been commented upon, with practical notes upon their use. Rodinal is a very concentrated single solution developer which is convenient for travelling, is always ready for use, and with care gives excellent results. It is not, I believe, in such general favour as some of the other developing agents, for the simple 3 38 A B C of Photography. reason tliat it is a single solution, the composition of which is unknown, and there seems to he somewhat of a prejudice against this class of developers, and further it is extremely energetic and it is necessar}^ to continue development for some considerable time in order to obtain sufficient density for ordinary printing purposes. For normal exposure it is advisable to use Rodinal. 1 drachm. In rase of over-exposure the amount of water should be reduced, and in extreme cases even to half the above quantity, and plenty of the 10 % solution of potussium bromide mentioned on p. 32., in fact if over-exposure is suspected, not less than 20 drops of the bromide solution should be added to the ounce of developer ; and should it be found that on application of this developer to the plate the image flashes up, at least three times this amount may be added to the developer without ill effects. For under-exposure and for all instantaneous work a more dilute developer should be used, and 1 strongly advise for this class of work that a developer composed of Rodinal 1 drachm. Water 5 ozs. should be first applied to the plate, and if the image is very slow in making its appearance, or only the high lights show, then more concentrated Rodinal may be added. By far the best method of using Rodinal is always to commence development with a developer composed of Rodinal 1 drachm. and in cases of under-exposure or instantaneous work this will ij;ive an excellent negative, whilst if the negative is over-exposed the developer can be strengthened by the addition of the following solution drop by drop. Water 20 Water 30 Development with Hydroqiwione, etc. 39 Uodinal 1 oz. Potassium bromide (dry) 160 grs. Water 1 oz. It is always as well to carry development with Rodinal rather farther thaii usual as the negatives seem to lose density in the fixiug-bath, but the factor given by Mr. Watkins on p. 47. may be adopted. Rodiual gives excellent results on bromide paper and lantern slides and for this work the following solution should be prepared Rodiual 1 drachm. Potassium bromide - 1 grain. W ater , 9 ozs. Many w^orkers, as we have already stated, object to the use of Rodinal because it gives great detail with somewhat thin negatives, and to overcome this it has been suggested tliat a mixture of Rodinal and hydrokinone should be used as follows No. 1. Sodium sulphite 2 ozs. Citric acid .... 5 grs. Potassium bromide 60 Hydrokinone 120 Vvater 20 ozs. No. 2. Rodinal 1 oz. Potassium carbonate 2 ozs. Water 20 „ Por normal w^ork mix the above in equal parts. For detail, increase the quantity of No. 2, and for density increase No. 1. The active principle of Rodinal is paramidophenol, which can be bought in the dvy form and made up either in a concentrated form like Rodinal or in two solutions, when it will work slower. The one solution strong developer can be made as follows and can be used in precisely the same way as Rodinal 40 AB C of Photography. Potassium metabisulpLite 1 oz. Water 31/2 oz3- Dissolve and add Paramidoplienol 154 grs. Then stir well and add enough of the following solution to dissolve the precipitate first formed Caustic soda 1 oz. Distilled water 2 ozs. The two solution developer is compounded of No. 1. Paramidophenol , % oz. Sodium sulphite 3 ozs. Distilled Water 84 „ No. 2. Potassium carbonate 4 ozs. Sodium sulphite 4 „ Distilled water 68 „ For use mix 1 oz. of No. 1 with 2 ozs. of No. 2. This developer works rather slowly, but gives very clean negatives and is very suitable for bromide paper. Diogen is one of the newer patented developers which is particularly recommended for the preparation of a one solution developer in concentrated form as follows Water 10 ozs. Sodium sulphite 4 „ Diogen 1 „ Potassium carbonate 5 „ Mix in the above order and filter the solutions, which Vv^ill keep for a long time. For correctly exposed plates dilute one part of the above with 4 parts of water and add, if necessary, a little potassium bromide. For under-exposure increase the quantity of water and omit the bromide, whilst for over-exposure either the amount of water must be decreased or, vfhat comes to the same thing, the quantity' of the above solution increased. Dei^elopment with Hydroquinone, etc, 4; Another patented developer, which is a strong solution of diamido-oxydiphenyl, is known as Diphenal, and this merely requires diluting with water and for correctly exposed plates in the proportion of Diphenal 1 part. "Water 20 — For over-exposure the amount of water may he reduced to one half, and for under-exposure increased to 25 to 30 parts. This developer has very little tendency to give fog but is on the other hand somewhat slow, a correctly exposed plate taking from 10 to 15 minutes to obtain the necessary density. The best, or what is certainly one of the best, of the newer developers is known as Ortol, which givea a negative more nearly the character obtained with pyro, without any danger of stain and it may be used over and over again; further it keeps well and is adaptable both for bromide paper and lantern slides and is I think the amateur's ideal developer. The image is not a pure black, but tends rather to a brownish black, and therefore it is of better printing quality and it is possible by modifying the developer to obtain any class of negative that one may desire. The particular formula that I recommend is No. 1. Ortol 70 grs. Potassium metabisulphite 35 Water 10 ozs. No. 2. Potassium carbonate 300 grs. Potassium bromide 5 „ Water 10 ozs. Tor quick development mix 1 part of No. 1 with 1 part No. 2; for slower and softer negatives mix equal parts of Nos. 1 and 2 and add half the quantity of water. The more of No. 1 that is used the harder the negative, the more of No. 2 and the more water the softer the results. For bromide paper and lantern slides the following should be used: 42 A B C of Photography. No. 1. Solution as on last page. . No. 2. Sodium carbonate II/4 ozs. Sodium sulphite. 2 „ Potassium bromide 10 grs. Water 10 ozs. For use Mix No. 1 . . . 1 part No. 2 1 — Water 1 — Hydrokinone BR is a mixture of hydrokinone and an alkaline bromide, but its action is totally different to a mixture of ordinary hydrokinone and bromide. It can be repeatedly used, gives good printing negatives, and the following formula will be fouud satisfactory No. 1. Hydrokinone BR V2 Sodium sulphite 4 — Water 25 — No. 2. Potassium carbonate 3 ozs. Water 25 ozs. For use mix 5 parts of No. 1, 5 parts of No. 2 and 4 parts of water. Por density mix in equal parts and do not add water, wliilst for softness increase the quantity of water. For bromide paper dilute with double the quantity of water. Another excellent developer w-hich is extremely convenient for travelling, in that a strong one-solution can be made, is Adurol: this gives a good black image, it keeps well, does not stain either the hands or film and is equally applicable to negative and positive work. Por a two-solution developer the following formula will be found satisfactory Development ivith Hydroquiuonej etc, 43 No. 1. Adarol 3 drachms. Sodium siiiphite 3 ozs. Water 19 „ No. 2. Potassium carbonate 2V4 ozs. Water 19 „ Tor instantaneous work mix in equal parts; for time exposures mix 1 part No. 1, 1 part No. 2 and 1 part water. In cases of over-exposure, a few drops 10 0/q solution of potassium bromide may be added. The single solution developer is made as follows: Potassium carbonate 21/2 ozs. Sodium sulphite II/4 „ Distilled water 7 ^ Shake till dissolved and then add Adurol V4 oz. For use dilute with from 5 — 7 parts of water, under-exposure requiring more water, and over-exposure less, and a few drops of potassium bromide solution should be added. Imogen-Sulphite is the latest addition to our developers, and is a faint pinkish powder which merely requires dissolving in water to form a stock solution, which is used in conjunction with a saturated solution of washing soda. No. 1. Imogen-Sulphite 1 oz. Warm water 12 ozs. No. 2. Saturated solution of washing soJa. To prepare this some ordinary washing soda should be placed in a bottle, and the latter filled up with warm water and the 44 A B C of Photography. bottle well shaken, there should always Le some undissolved soda at the bottom of the bottle so as to ensure that the solution is saturated. For correct exposure mix No. 1 2 ozs. No. 2 1 oz. For under-exposure use No. 1 2 ozs. No. 2 1 oz. Water 2 ozs. Por over-exposure use No. 1 2 ozs. No. 2 1 oz. Potassium bromide 10 sol I/4 „ If great density is required in the negatives use No. 1 1 oz. No. 2 1 ., Potassium bromide 10 % sol 10 drops. This developer gives a good black and white image, and by dilution with an equal quantity of water may be used for bromide paper. Amidol is now the only developer left to treat of, and this has been purposely left to the last, because it is totally different to all the other developers. Hitherto we have seen that an al- kaline accelerator has been required; with amidol no alkali is needed. Amidol will not keep well in solution, but soon loses its developing power; it is advisable therefore to dissolve it only as required for use, as follows: Stock Sulphite Solution. Sodium sulphite . . Distilled or boiled water to 21/2 ozs. 8 „ Development with Hydroqiiinoiie, etc. 45 To make the developer, take 100 i-ninims of the above solution, make up to 1 oz. with water, and add 21/2 gi's« «f dry amidol, and resn-ainer as in the case of pyro. The morie sulphite used the quicker and more energetic the development, whilst if a very pow'erful restrainer is required, about ten drops of a solution of citric acid may be added, made by dissolving 1 oz. of c trio acid in 9 ozs. of water. CHAPTER X. Duration of Deyelopment. The question how long to continue development has been, almost since the first commencement of photography, a difficult one, not only for beginners, but also for advanced workers. Mr. Watkins has discovered a method of timing development, however, which now places in the hands of beginners far greater power than was previously the case. The old methods of es- timating the proper point at which to stop development were either to look at the back of the plate and see whether the high lights and the principal half tones showed through, or to examine the negative held up to the dark-room light and judge of its density by experience and^ memory of past work. The objection to the first method is that the appearance of the high lights through the back of the plate depends primarily upon the thickness and opacity of the film of emulsion, and also that subjects with very great contrast show much more distinctly than those of a more harmonious nature. The objection to the second method is of course that a beginner has no experience of past work and it is difficult even for old hands to carry in their minds the exact appearance of past negatives. Mr. Watkins system is applicable to all developers except pyro-ammonia, which is unstable in consequence of the evaporation of the ammonia whilst development is proceeding. As soon as the developer is applied to the plate the time should be carefully Duration of Development. 47 noted with a watch provided with a seconds hand, and the dish rocked and the plate carefully watched for the first sign of any image, and again the time noted. ^ Mr. Watkins has placed on the market a small clock, which he calls the Eikronometer, specially designed for nse with his system, and which is provided with one hand which revolves once in ten minutes. On the glass, which will readily revolve under pressure from the fingers, a black indicator, which is set to the total time of development. When the developer is mixed the hand of the clock is moved by means of a milled head till it is just upon the 0, as soon as it touches this figure, the developer should be poured over the plate and development allowed to proceed. When the first sign of any image is seen the time by the dial is noted, and this is multiplied by a factor which is correct for the particular developer used. The factors for the various developers are as follows: Factor Pyro soda, 1 gr. pyro, I/4 gr. bromide. . 9 w ;/ 2 7; . V w V • • V 3 „ „ 3/^ „ ^, 4V2 V „ 4 „ 1 „ „ . . 4 V 8 „ „ 2 „ „ . . 31/4 Ilford, full pyro 41/2 »/ half „ 5V2 Adurol 5 Kachin 9 Hydroquinone 5I/4 Eikonogen 9 Metol „ 30 Glycin , .... 7 Amidol (2 gr.) 18 Rodinal 40 Ortol 10 Metol-Hydroquinone 14 Cyrocatechine 9 Pyro-Metol 9 48 A B C of Photography. As an example to show the working we will assume that we are using pyro-metol: the first trace of an image appears in 13 seconds, then 13 X 9 = 117 seconds. which will be the total time of development required to produce a vigorous negative from average plates. The above factors are calculated for developers of about the following strengths -per oz. of developer. Pyro 2 grains 8 I/2 12 Carb. Soda Eikonogen 6 „ 24 I/4 10 „ Potash Hydroquinone 2 „ 8 — 2 Caustic Soda Metol 2 „ 16 2 20 Carb. Soda Amidol (dry) 2 „ 24 I/2 Increase in temperature or dilution of the developer makes no difference, but if the quantity of bromide is increased the factor is reduced. It must be distinctly understood that the developing factors given above are simply those which have been generally found to be the most useful; it may happen that after working for some little time the operator may find that they give negatives which are too thin or too dense, then of course a higher or lower factor may be employed to suit the individual taste of the worker. After considerable experience in photography, and an extended trial of this system of timing development, I most strongly urge every beginner to adopt it. I believe it to be one of the most useful and valuable aids to successful work which has been introduced for a very long time. Many old workers will sneer at it and say that it is quite unnecessary and others will say that it reduces photography to a purely mechanical art. I myself looked upon it with consid- erable suspicion at first, but I am convinced that those who adopt it will save many a negative if beginners, and if old hands, will be able to obtain far more regular and even printing negatives. CHAPTER XT. Modifications of the Developer. It is only when we come to develop the plate tliat we find out whether we have correctly calculated the exposure; and it is lucky for us that, by altering the quantities of the various ingredients, we can to some extent remedy our mistakes in exposure. There are practically three conditions of exposure — correct, under-exposure and over-exposure, and these we will proceed to describe. A correctly exposed plate when correctly developed shows the high lights of the picture in about forty to sixty seconds in the developer, these gradually grow in blackness or density and the half tones gradually appear and strengthen, and the shadows grad- ually come out till the development has continued long enough and there is little or no while to be seen on the film. In cases of under-exposure, the high lights are a little longer in appearing, being followed by the brighter half tones more slowly, but the darker shadows and deepest shadows remain ob- stinately white and unaffected. This would be described as a case of gross under-exposure. It may happen that we have only slightly uuder-exposed, and then development proceeds regularly, though a little more slowly than in the case of correct ex- posure, but still the very deepest shadows refuse to show any- thing but the annoying white appearance. Over-exposure^ when great over-exposure has been given, so AB C of Photography, cannot be mistaken. As soon as the developer is applied to the plate, the image appears at once, the half tones almost as quickly as the high lights, and then the shadows, and the whole plate quickly becomes covered with a grey film or fog. In cases of slight over-exposure, the image does not appear quite so quickly, bat still too quick, and the result when finished is by no means satisfactory or bright. The plate is foggy-looking, and minor difterences are tp be noted which cannot be mistaken and w^hich will be alluded to hereafter In the case of correct exposure, any of the normal developers may be allowed to act for their full time, and in almost all cases, there will be found under the developing formulae, instruc- tions how they can be modified for over- and under-exposure and it will be very easy to modify the normal developer in accordance with these instructions, by merely adding the neccessary quantity of water, bromide or developer, or, if preferred, the developing dish may be at once put under the tap and this turned on full and allowed to run whilst a fresh developer is mixed. For slight under-exposure it will be found that by increasing the amount of acceleator fairly satisfactory results can be ob- tained, such at least as, with a little dodging in printing, will give good results. It must be accepted as an axiom that nothing will really compensate for under-exposure. The reason for this is, that to enable the developer to reduce the silver bromide in the film to the metallic state, which is what actually tnkes place, it is necessary for it to be affected or acted upon^by light, and if w^e have not given sufficient exposure, that is, not allowed enough time for the light to act, no alteration of the con- stituents of the developer will do what the light should have done. Over-exposure is far more easy to correct, and should the image, on the application of the developer, immediately begin to rush out, the dish should be instantly filled right u]) with water, the whole poured away, and a fresh developer composed of pyro 8 Modifications of the Developer. 5' grains, potassium bromide 4 grs., water 1 oz. with one-fourtli the normal quantity of accelerator, poured over it. When the over-exposure is slight, which wiir he known by the image appearing rather too rapidly, double the usual quantity of pyro and restrainer should be poured into a measure, the developer from the dish mixed with it, and the whole returned to the plate. The appearance of a correctly exposed negative can hardly be described so as to convey an intelligible idea to a tyro. There should be very little, if any, clear unalFected film, and the grad- ation or transition from the deepest shadows to the highest light should be very gradual. In under-t xposure, the gradation is very sudden, or, as we call it, the contrasts between the lights and shadows are very harsh. With over-exposure, on the other hand, the contrasts are poor, the transition from high lights to shadows is not so marked because the shadows have been so much affect- ed by light as to catch up the high lights. We can practically formulate a series of elastic rules which will be useful for beginneis, whilst the more expert hand will be able from his own experience to modify development to suit varying subjects and exposures. For correct exposure use the normal developer. For under- exposure reduce the restrainer and increase the alkali. For over- exposure increase the developing agent proper, and the restrainer, and reduce the accelerator. The above directions must be used 'with brains'. At first they may be rigidly adhered to, but later on as experience is gained, it will be found possible to play all sorts of variations on the proportions of developers to suit the plate and the ex- posure and subject as will be seen necessary from the appear- ance of the image. There is one method of development which is very easy to work, which gives excellent results with very little expenditure of 'brains', and it is called 'stand development'. It is most suitable for those who have a lot of plates to develop and not much time to spen l on it. It is to a great extent mechanical. It cannot be carried out in the ordinary flat dishes, but up- 52 A B C of Photography, right grooved |;orcelain troughs should be used. Any of the developers suggested in the previous chapter may be used, but far more diluted. Glycine gives the best results by this method. The actual developers sugoested in the previous chapter may be made up, and then four times the quantity of water aided. The dilute developer should be poured into the trough, and the plates quickly inserted in the grooves, and a piece of wood or opaque card placed over the top. The developer must be at least a quarter of an iuch above the edge of the glass. In about fifteen minutes — during which time, of course, other things may be done — the plates shoull be lifted out and looked at, and from their appearance the necessary time fixed. Over-exposed plates will probably in this time be nearly complete, whilst the correctly 3xposed and those under-exposed will take longer, even up to half an hour. This method of development is one I can strongly recom- mend for beginners. There is no trouble about alteration of the proportions of the developer ingredients, the process goes on quickly by itself, and if the trough is covered over with a wooden or cardboard lid, the dark room may be left and any work outside undertaken. CHAPTER XI 1. Fixing, Clearing, Washing, The plate after exposure and development still contains some silver salt whicli lias not been reduced by tbe developer and whicb is still sensitive to ligbt, this is dissolved out, or as it is technically termed, the plate is fixed. For this purpose a solution of hyposulphite of soda, usually known as 'hypo', is used. As soon as the plate has been sufficiently developed, it should be rinsed uuder a tap and then placed in the fixing bath, the ordinary formula for which is Hyposulphite of soda 4 ozs. Water 20 ozs. Hypo is extremely cheap, seven pounds usually costing a shil- ling. It is as well therefore to make up a good quantity of this solution, and for this purpose purchase from a chemist a large bottle known as a Winchester quart, which really holds half a gallon, or eighty fluid ounces. Weigh out one pound of hypo and put it in a clean enamelled iron saucepan, pour on to it about three pints of water, then p^ace on the fire and stir with a piece of wood; as soon as it is all dissolved and has become cool, measure it out and add suffi- cient cold water to make the total bulk measure eighty ounces, and then bottle. Personally I never use th^'s bath, preferring for all negative work the acid fixing bath, which is made as follows: Dissolve 54 A B C of Photography. 1/4 ounce of citric acid in 1 oz. of hot water, 1/2 oz. of sodium sulphite in 1 oz. of hot water, mix the two solutions, and add the mixture to one pint of hypo solution made by dissolving 5 ozs. of hypo in sufficient water to make one pint. The advantage of the acid fixing bath is that it not only keeps clean itself longer, but also prevents the negatives from becoming stained by any oxidation of the developing agent. It also hardens the gelatine and thus prevents frilling and blistering to which it is sometimes liable in summer. Some operators prefer to use a bath containinor alum for the same purpose, but this is unnecessary. The following formula will, however, be found satisfactory : Sodium bisulphite ., 2 ozs. Water 8 ozs. Dissolve and add Chrome alum 1/2 oz. Citric acid I/2 oz. Water • 10 ozs. And mix with the above Hypo 4 ozs. Water 8 ozs. The plate sbould be allowed to remain in the fixing bath for at least ten minutes after every trace of the whitish yellow silver salt has disappeared, and it should not be examined by white light till after this time. Many operators think the last precaution unnecessary, but there is a slight change when a half-fixed plate is examined by white light, which is not beneficial. Instead of using the ordinary flat dishes for fixing, the upright ebonite or porcelain troughs will be found much more convenient, taking up little, if any, more area on the bench, and yet allowing more plates to be fixed at once : and dirt and dust can be more readily kept out of them by covering over. A fixing bath should not be used too long ; hypo is now so cheap that it is false economy to keep on using a bath after it has become dirty, and it must be remembered that the more plates Fixing, Clearing, Washing. 55 fixed in a bath, the weaker are its solvent powers npou the unaf- fected salt. Hypo is almost indispensable to the photographer. No efficient substitute for it has yet been found, though many have tried for years to find out something to take its place. In its proper place hypo is an invaluable servant, but when it becomes dirt, that is matter in the wrong place, then it will ruin every thing. Mere traces of hypo in the developer will cause a plate to fog and be useless, therefore care should be exercised to keep the developing dishes clean. If the fingers are placed in the fixing bath for the purpose of puttin;? in or taking out a plate they should be well washed prior to touching any- thing else. The solution should not be slopped all over the bench, and it is advisable to keep a small sponge haudy where- with to wipe up any trace of solution, whether hypo or developer, which may be accidentally spilt. As soon as the negatives are properly fixed, they should be set to wash. There are many forms of specially constructed tanks for washing negatives, and one of these will be found extremely convenient, but makeshift washers may be constructed. A large earthenware pan, such as is frequently used in households for keeping bread in, may be obtained; and the negatives placed all round the inside of one of these, with the film towards the side, provided a fairly large-bore india-rubber tube is fixed on to the water-tap of the sink or any water supply not necessarily in the dark room, and placed in the pan with the end lying on the bottom. If the tap is turned on, a constant stream of fresh water will flow in through the pipe, and the excess of water will run over the top of the pan. Failing this, an ordinary flat dish, or even the grooved porcelain tank, may be used as long as the water is frequently changed; it is very essential that this should take place, otherwise the hypo will not be properly removed, and the negatives will fade and become useless ill time. So essential is the removal of the hypo that not only is it sometimes recommended to wash the negatives fur some three or four hours, but numerous chemicals have been suggested 56 A B C of Photography, with whicli to treat the negatives so as to chemically destroy the last traces of. hyj)o. Of these there is only one which is really satisfactory and harmless, and this is persulphate of potash, or, as it is generally called, 'Anthion'; and 1 should strongly recommend the use of this for not only saving time, but also water, and making the chance of the negatives fading consider- ably less. Dissolve 50 grs. of anthion in a pint of water. After the negatives have been fixed they should be washed in running water for ten minutes, then soaked for five minutes in the above solution of anthion, rinsed, and this operation repeated three times; then finally washed for quarter of an hour, and set up to dry in a fairly warm place free from dust. In drying negatives it is advisable to dry them in as even a temperature as possible; that is to say, they must not be partially dried on a shelf aud then finished off before the fire, or else irregular lines will be formed which nothing will eradicate, and which will entirely spoil any chance of getting good prints. On a mantelpiece, or shelf of any kind near the fire, in winter, is a good place, but in summer they should be dried in the shade in a current of air from a window. When the acid fixing bath is not used, or when it has become old and discoloured, particularly if pyro is used, it will be found, frequently, that the gelatine is stained a deep yellow, which in the after operation of printing is often prejudicial, if the negative has been properly developed. If it is under- developed the yellow stain will often be an advantage. To remove this stain, certain solutions, called clearing baths, are used, and I give two satisfactory formulae. Chrome Alum Clearing-bath. Chrome alum 1 oz. Citric acid 1 oz. Water 20 ozs. Dissolve, if necessary, by heat. After the negative has been washed it should be placed in a dish and flooded with the above solution, which should be Fixing, Clearing, Washing, 57 allowed to act for about ten minutes, and the negative again well washed and then dried. Another good formula is: Thiocarbamid 30 grs. Citric acid 10 grs. Chrome alum 30 — Water 5 ozs. This should be applied like the other, but only allowed to act for about five minutes. CHAPTER XIII. Intensification and Reduction. When from errors in exposure or development we find onr negatives very thin and giving flat prints, we have to increase the density or opacity of the image by a process called intensifi- cation. This is done by addiug some substance to the image, which will either alter its color or its darkness. The negative after having been thoroughly well washed and treated with anthion, should be doctored by one of the following methods. If the negative has been dried, it should be soaked in plain water for ten minutes before treatment. Dissolve the ammonium chloride in the water, add the mercury and allow it to stand, with an occasional shake, till dissolved. Label the bottle " Solution of Mercuric Chloride — Poison Great cave must be observed when using this solution as it is a deadly poison. When not in use it should be kept locked up; and when in use, the fingers should not be kept in it longer than is absolutely necessary; for if there are any cuts or abrasions of the skin it may be absorbed and give rise^ to mercurial poisoning. The negative to be intensified should be placed in a dish, The Mercury Solution. Mercuric chloride Ammonium chloride Distilled or boiled Water 100 grs, 100 — 10 ozs. Intensification and Reduction. 59 covered well with the solution and left till, on lifting it out and looking at it through the glass, the image appears quite white. It should then be well washed in running water for at least a quarter of an hour, and then treated with a 5 per cent, solution of sodium sulphite, made by dissolving 1 oz. of sodium sulphite in a pint of water. In this solution the negative soon turns dark brown or black, and it should be lelt in the solution till, on examining the back through the glass, it is seen that it has darkened everywhere. This, which is called the sulphite intensifier, is useful where only a little reinforcement is required — when considerably more intensification is required it will be advisable to use in- stead of the sulphite, a 5 per cent, solution of strong ammonia. One of the most satisfactory of all intensifiers is that known as Monckhoven's — which is also very poisonous. The negative is bleached in the mercury as described above, well washed and then blackened in the following: Silver nitrate 200 grs. Distilled water 10 ozs. And add gradually Potassium cyanide , 200 grs. Distilled water 10 ozs. Immediately on adding the second to the first solution a white flaky substance will separate out in the solution, which should be shaken up after each addition of the second solution; as more of the, latter is added it will be found that the white precipitate will begin to dissolve, and as soon as there is only a little of the white flaky substance left the solution is ready, and no more of the second solution should be added. After intensifying by all these methods, the negative must be thoroughly well washed and dried. There are two other methods which may be adopted and which are not quite so poisonous. The first of these is very vigorous and should not be used unless very great intensification is required, or else the negative will become so dense as to be rather troublesome to print. 6o AB C of Photography. Potassium ferridcyanide 48 gis. Uranium nitrate 4S „ Glacial acetic acid 1 oz. Distilled or boiled water 10 ozs. The negative must be well washed and freed from hypo as previously described, and then immersed in the above solution, in which it will turn a reddish brown. This should not be allowed to act too long; the negative then should be removed, well rinsed, not washed for very long, and then dried. The advantage of this process of inlensification is that if it is found to be unsatisfactory or the negative has been intensified too much, it can be entirely removed by washing in a 5 per cent, solution of ammonia and can then be intensified again aft#r washing, by this or any other method. The second method is by using the following solutions: No. 1. Potassium bromide 120 grs. Distilled water 10 ozs. No. 2. Copper sulphate . 240 grs. Water 10 ozs. Mix the two solutions, and in this bleach the negative, rinse once of twice, and then blacken in Silver nitrate. Distilled water and then thoroughly wash and dry. Another excellent intensifier is the mercuric iodide as modified by Lumiere, it is easy to make, keeps well in the dark and is simple to use. It is prepared as follows: Mercuric chloride 51 grs. Distilled water 4 ozs. Dissolve and add Potassium iodide 41 grs. Distilled water 1 oz. 300 grs. 10 ozs. Intensification and Reduction. 6i a brilliant red precipitate will be formed, and tbis sbould be allowed to settle to tbe bottom of the measure and the supernatant clear liquid poured or sypboned carefully off, and tbcn tbe following S'jlution added Sodium sulphite 2 ozs. Water 20 „ In this the negative is to be immersed till bleached, tben wasbed well and redeveloped with any old used developer. The .ibove metbods of intensification if properly carried out will be found to give every satisfaction, provided that the direc- tions are carefully heeded. Slovenliness and carelesness of working is never more likely to spoil results than in intensification. Sometimes it happens that tbe plate has been allowed to remain in the developer too long so that it has become too dense or opaque. Then we must reduce it. As in intensificalion so in reduction, tbere are several metbods by whicb ^t can be done. The simplest and best is that suggested by Belitzki: Potassium ferric oxalate •^/2 oz. Sodium sulphite 180 grs. "Water 10 ozs. Dissolve and add Oxalic acid (crystals) 30 grs. Before adding tbe acid the solution is a fine blood-red color, and on adding the acid and shakiog it, it gradually pales in color and turns green, wben it sbould be poured off from any undissolved acid; tben add Sodium hyposulpbite Dissolved in water. . and bottle it. This mny be applied to a negative immediately after fixing, or to a negative which bas been dried, provided it is soaked in water first; and the solution keeps well and can be used over and over again. 21/2 ozs. 62 A B C of Photography. Howard Farmer's reducer is simple, although somewhat energetic. Do not make up much of this solution as it readily spoils. Place the negative in a dish and cover it with a mixture of clean liypo solution 1 oz.j water 4 ozs., and then into a measure drop twenty or tliirty drops of the above solution and add the hypo to this, and return on to the negative. It will be seen that the negative gets gradually thinner, and by adding more of the ferridcyanide solution the action may be hastened. Before the negative is quite thin enough, remove and wash well. Another good and slow-acting reducer is Lainer's Iodide Reducer. Potassium iodide 10 grs. This should be flowed over the negative, and when reduction has proceeded far enough, it should be well washed and then set up to dry. Potassium ferridcyanide. Distilled water 60 grs, 11/2 oz. Sodium hyposulphite Water 1/2 oz. 21/2 ozs. CHAPTER XIV. Varnishing, Spotting Out, and Ketoucliing J^egatires. It is almost a mattei* of creed for old photographers to var- nish their negatives, but the rising generation do not take so much trouble on this point, though they should do so. The object of varnishing is to prevent accidental scratches or other mechanical injury to the film, and to prevent it from being stained whilst printing. There are many kinds of varnishes on the market which are good and reliable, but for those who may be desirous of making their own I append two formulae. Shellac Varnish. Gum sandarac 1 oz. Shellac I/2 oz. Castor oil II/2 drachm. Methylated alcohol 1 pint. Place the ingredients in a bottle and allow to stand till dis- solved, shaking frequently. Zapon Varnish. Pyroxylin or celluloid 50 grs. Amyl alcohol 5 ozs. Amyl acetate 5 ozs. Allow to stand, shaking frequently, till dissolved. The cellu- loid for this should be the thin transparent celluloid which is used instead of glass for photograjh c plates. 64 A B C of Photography. It requires some considerable practice and knack to success- fully varnish a negative with the above, and therefore I give another recipe for v^^bat is called Cold Varnisb. White bard varnisb 5 ozs. Strong solution of ammonia q. s. Add sufficient solution of ammonia to make the varnisb be- come quite clear on shaking. On first adding tbe ammonia, the varnisb becomes thick and milky. To apply the first varnisb the negative sbould be beated in front of tbe fire till it is just comfortably hot to tbe back of tbe hand, it should then be supported on tbe tips of tbe fingers of the left band and a fairly large pool of varnisb poured into tbe middle of the negative. ]3y tilting tbe negative, tbe varnisb sbould be made to run first to tbe right-hand corner furthest from you, tben to tbe left- band corner furthest from you, then to tbe left-band comer nearest you, and finally to tbe bottom right-band corner, and tben tilted sufficiently to allow tbe ex- cess to run ofi" into tbe bottle. I have said this requires some practice. I strongly advise those who wisb to attempt this to turn up their sleeves and operate over a good-sized dish, or seVeral thicknesses of paper, because, as likely as not, as mucb varnisb will run up tbe arm and on to tbe paper as will stop on tbe negative, but with a little practice, success will be obtained. Afier draining off tbe excess varnisb, tbe negative sbould be reared up in front of a fire to dry. Zapon varnisb may be applied without heating tbe negative, but otherwise in exactly the same way as described above. It gives an exceedingly bard, good, protective coating, but has the disadvantage of smelling very strongly of what is commonly known as 'pear drop essence', wbicb is to some people exceed- ingly disagreeable; and further it takes a very long time to dry — four or five hours at least in front of a good fire. The cold varnisb has none of these disadvantages; tbe only one being that it does not give quite such a good protective Varnishing, Spotting Out, etc. 65 coating. A pool of this varnisli may be poured on to the middle of the negative and then distributed with a brush, a soft camel- hair varnish mop is about the best, to use. Should any varnish by accident get on to the glass of the negative, it may, when quite hard, be easily scraped off with a knife. Spotting a negative is a technical term used to denote the spotting or blocking out of small defects, such as little trans- parent spots. This is usually done with water-colors before varnishing. Either the moist pan or dry-cake colors may be used. A very fine camel-hair or red sable brush is required, and also a little gum water, which can be made by dissolving a few lumps of good gum arable in water. An ordinary house- hold plate or saucer may be used as a palette. The brush should be dipped into the gum water and then the excess of gum squeezed out, not much is wanted on the brush ; a little color should now be taken up on the brush and dabbed on to the saucer or plate. The best colors to obtain are gamboge, carmine, vandyke brown, ultramarine, and black. With thes3 colors it will be possible to match the color of the image of the silver image exactly. This is rather an important point, as the spotting out may show afterwards in printing. By supporting the negative as suggested hereafter for retouching, and using a white surface like a plate or saucer, it will not be difficult to match any color. Enough of each color should be taken up on the brush, the whole mixed up together on the palette till quite thick, and then the brush drawn out to a fine point by turning it round, and the very point of the brush charged with color used. Do not attempt to fill up a hole with one touch, but rather stipple the color in, that is, just touch the hole with the point of the brush, making as fine a dot as possible. Then proceed to treat other holes in like manner, or if there is not more than one hole, wait a little time and then add another dot by the side of the first. Ear better results will be obtained by thus spotting out than by putting one dab of paint over a hole. Sometimes it is desirable to block out the sky of a negative, particularly when separate clouds are to be printed in, a subject 66 A B C of Photography. whicli will be treated of hereafter. For this jjurpose a draughts- man's or crowquill pen and some black varnish, which can be obtained from any dealer, should be j^urchased. The negative should be placed on the retouching desk or makeshift easel, film towards the worker, and upside down. To charge the pen with varnish it should not be dipped into the bottle, but a fine brush should be used, this should be dipped into the varnish and thtn wiped on to the pen; by working in this way blobs of varnish are pre\ented from running otf the pen. With the pen thus charged with varnish carefully trace round the outline of the landscape, particular attention being paid to keeping strictly to the outline and not encroaching on the image. With a little care and practice this soon becomes an easy matter. As soon as all the outline has been traced round, use the brush not too full of varnish, and again go round the outlines, taking care not to encroach on the line previously drawn. The line made by the brush will, of course, be broader than that of the pen; the use of the latter first being to enable finer tracing to be done. Now using a fairly large bru^h, work all over the open expanse of the sky with the varnish, and allow to dry. Retouching is one of those little dodges by means of which professional photographers make such nice-looking prints, by means of which they smooth out our wrinkles, take out an obtrusive mole and destroy the measle-like freckle. It is not such an-jeasy process, and I must and can only give plain simple directions which will set the beginner into the right paths, so that he can with practice attain something like perfection. It must be remembered that nature does not give us smooth ivory skirs, that care and thought and spiteful old age will imprint crows- feet and wrinkles, and that to obliterate these entirely means taking away the entire character of the face. Just imagine the Chehea sage, Thomas Carlyle, without his wriiil^les. Very cheap retouching desks can be obtained now, but for those who desire to use a makeshift arrangement, an ordinary printing-frame of the size of the negative, may be used. If the back is removed with the springs and the frame supported at an angle of about 53° it will be found very convenient, but Varnishing, Spotting Out, etc. 67 a large piece of cardboard should be nailed to the top of the frame aud thin black cloth curtains be glued to the sides so as to prevent any light except that which comes through the negative from reaching the eye. The frame may be supported on blocks of wood. Behind the frame should be laid flat on the table a piece of white paper or opal glass. The negative must be prepared for retouching and for this purpose some commercial retouching medium may be obtained, or the following substitute used: — Gum dammar 96 grs. Turpentine 1 oz. When this is dissolved, which it will do fairly rapidly with occasional shaking, you will have a good retouching medium which will last for years, for very little is required. The bottle of medium should be opened, the first finger of the right hand placed on the mouth, and the bottle turned upside down, and the finger drawn lightly across the neck of the bottle and then rubbed with a circular motion over the face or other part of the negative to be letouched, till the medium is nearly dry. It may then be allowed to dry thoroughly. Lead pencils are used for retouching and one or two special retouching pencils should be bought, preferably those in cedar, HH, or H. It is not a very easy matter to sharpen a pencil properly. The following is the proper way : Avith a sharp knife begin to cut away the wood about an inch and a half from the end; slice the wood off as evenly as possible all round, and, when only a thin section of wood remains near the point, lay the pencil down on a firm support like a table : hold it firmly with the left hand, and the knife in the right, with the edge towards you, and now begin to shave the wood ofi" from the point. As soon a^ about half or three-quarters of an inch of lead is laid bare, pocket your knife, it is no longer wanted. Now lay a piece of coarse emery or rather fine snnd paper flat on the table, and holding this down with the left hand, rub the pencil up and down, turning it round lU the time. Keep the pencil as flat as possible, the great idea being to obtain as long 68 A B C of Photography. a point as possible. As soon as the lead begins to gain a point, replace the coarse paper by some of the finest emery p^'per, or fine ground glass and work in the same way. A well-sharpened pencil should have about an inch of wood tapering down to about half an inch of lead, which should end in a hair-like point. If the spot to be retouched is large, we want totally different work to a small spot. For instance, suppose we have a portrait and we find on printing that one side of the face is very dark and the other very light. The < bject of retouching is so to work on the negative as to bring the two into softer harmony. In this case, the side of the face which in the negative is thin- nest is the one to be w^orked up. Commence with fine wavy lines running along the curve and following the curve of the cheek; it is just as well to use a fairly strong reading-glass to put these lines in; they should be as fine as possible and as close together as possible, and after working all in one direction cross the direction of the lines. Instead of using lines we may use stipple, a little dot or fine comma-like marks close together. After having retouched one place, take a rough print from the negative. If the retouching shows too much, it can all be removed with a rag dipped in turpentine and the work started again. Remember that the finer the lines and the less w^ork you put on the negative film the better. Freckles and little transparent spo*s may be evened out with light touches with the point of the pencil hdd almost upright, at least at right angles to the negative. Always be careful to keep the point as sharp as possible, and for this purpose either the ground glass or fine emery paper should always be close at hand. By using the pencil rather heavily, the hair may be lightened, or if very large masses are to be lightened, then the flat of the pencil may be used and the place rubbed over very lightly, or better still, the 'tip of the finger may be rubbed on to the emery paper or ground glass till black, and then this dabbed all over the place, the retouching medium very soon takes up the powder and the space becomes covered. CHAPTER XV. Printing on ilbumenized Paper. Having obtained the negative and carefully doctored^ or spotted it out, the beginner will of course be extremely anxious to print from it. There are so many printing processes that we shall have to devote considerable amount of space to them. In this chapter we shall consider mainly some of the maxims of print- ing in general, and what is called albumenized-paper printing in particular. In the first place there are two distinct kinds of printing processes ; the one class being what is called printing out pro- cesses, the other development processes. With all those papers belonging to the first class the image is visible on the paper and can be examined from time to time during the progress of printing to see that all is going on smoothly. With the second class, the image is invisible as with a dry plate, and has to be treated with certain chemicals before it can be seen. The first class is by far the easier for a beginner to tackle. Printing-frames can be obtained very cheaply now, for a few pence, and two or three of the desired size should be bought. The negative should be laid flat on a piece of white paper and the back or glass well cleaned with a damp cloth, for it fre- quently happens that a little gelatine gets on the back of the glass when it is being coated by the manufacturer. It should then be place! in the printing-frame with the film inwards. Albumenized paper can be bought in sheets measuring 17x22 4 70 A B C of Photography . inclies, but it will be found far better to purchase it already cut up to size, for it is delicate stuff to handle and readily spoils by contact with dirty or greasy fingers. It must be re- membered that the paper is serifcitive to light, aud therefore it should only be exposed to very weak daylight. There will be no difficulty in telling which is the prepared side, it is very bright and glossy, this side should be placed in contact with the film of the negative. One or two pitces of blotting paper cut to size should bs placed on top of ihe paper, and then the back of the printing-frame put in position and the springs fastened down. The frame should now be placed in the light to print. One of the best places is on a windows-sill facing north. It may be taken almost as an axiom that direct sunlight should never be used for printing. A soft diffused light is far better. The frame should be left on the window-sill for some little time, say for fifteen minutes, and then the paper examined. For this purpose remove the frame from the window, w^here the direct light will not fall on to it, undo one of the springs only, turn back one half of the back, taking care not to shift, the other side at all, then gently lift the paper up and look at the face of it. By this time the picture, or at least as much of it as you can see, should be distinctly visible; but do not be in a hurry, give it plenty of time to get what is called a rich intense print. There is not, unfortunately, any golden rule as to how long to continue printing, but as a general rule it may be considered that printing should be carried on till the shadows are blocked aad the high lights decidedly tinged. For instance- supposing that the negative represents a man in a black coat with white ollar and cuffs. Printing should be carried on till you can see practically no folds or pattern in the coat, and un- til the culFs or collar show a decided tinge of color. The albumenized paper prints out to a peculiar chocolate brown color, which is very characteristic, and wdth a little ex- perience one soon learns exactly how far to carry printing, to obtain the best results. I assume that more than one print from the same negative Printing on Albumenized Paper. 7* will be required, or that prints from two or three negatives are wanted. As soon as you ihink the paper is printed enough, retire from the window, undo both springs of the frame, remove the blotting paper, lift up the print, place it in an empty plate box, and put away in a drawer so as to keep light and air from it as much as possible. Proceed in this way till you have at least half a dozen or a dozen prints ready. The prints are of a somewhat unpleasant foxy red or chocolate colour, and are of course still sensitive to light, and therefore they have to undergo certain operations called 'tonicg' and fixing. Toning is merely the alteration of the color by depositing metallic gold in an extremely fine state of division on to the image. When in a fine state of division gold is not of the ordinary bright yellow color, but a deep blue black, and this combining with the color of the silver image gives us those well-known tones, as we technically call the colors of ordinary photographs. The process of toning can be carried out in ordinary day- light as long as it is not too bright. It should not be per- formed by artificial light as it is far more difficult to follow. For toning we require some chloride of gold. As every one knows, gold is rather expensive ; but the chloride of gold can be bought in little glass tubes containing fifteen grains for about two shillings. One of these tubes should be purchased and a scratch made across the middle with a three-cornered file. If the tube is now placed in a two ounce measure and struck rather sharply just at the file mark, with a table-knife handle or end of a silver spoon, it will break. One ounce of distillel Waaler should now be poured into the measure, the whole stirred with a glass rod, and the solution poured off into a two-ounce bott'e. Half an ounce of distilled water should be put in^o the measure, again stirred and then poured into the bottle con- taining the ounce just used. A further quantity, three drachms, of distilled water should be measured out in the same way as before and put into the bottle, making fifteen drachms in all. Label the bottle Solution of Chloride of Gold. One drachm 72 A B C of Photography contains 1 grain of Chloride of Gold." This, for convenience, we will call the stock gold solution. It must be kept from the light, and therefore brown paper may be pasted over ihe bottle, or else it can be kept in the dark room. The number of formula? for toning-baths is legion, but pur- suing the plan followed throughout in this little work, I shall content myself with giving three or four well-tried formulae, which I know from per.-onal experience will work well. The Acetate Toning Bath. Chloride of gold 1 grain Acetate of soda 30 grs. Distilled water.. 10 ozs. Dissolve the acetate in the water, measure out 1 drachm of the stock solution of gold, add it to the soda solution, and let the mixture stand twenty -four hours before using. If the bath is required for immediate use, the water should be just boiled, the soda and gold added, and used as soon as cold. The Phosphate Bath. Chloride of gold 1 gr. Sodium phosphate 20 grs. Distilled water 10 ozs. This bath may be used as soon as it is mixed. The Compound Bath. No. 1. Borax in powder 330 grs. Acetate of soda 180 Bicarbonate of soda 90 „ Distilled water 20 ozs. The Toning Bath. No. 1 solution II/4 oz. Chloride of gold 1 gr. Distilled water 10 ozs. Mix two hours before using. When these baths have been used for toning prints, they Printing on Alhiimenized Pater. should be placed in a bottle, and used insteadof water for making the next bath. They may be used in this way at least six or eight times ; each time, of course, fresh gold and soda, etc., must be added. We are now ready for toning: the toning bath is made, the prints are printed. Take two dishes of the required size, and see that they are perfectly clean. The least tiace of dirt or chemicals will spoil the toning bath, so it is just as well to keep one dish for nothing else but toning, and it should be marked in some way; if made of glass or porcelain, it will be easy to paint a big T in black varnish on the bottom; if of vulcanite the letter may be scratched on with a knife or other sharp pointed instrument. Make a solution of washing soda 1/4 oz., water 1 pint, nearly fill one dish with this solution. In the other dish place your toning bath. Take hold of a print by an extreme corner, and remember when handling prints, that this is the only way to touch prints or paper, then lower it into the soda solution face downwards, and thrust it under the surface of the water with the finger-tips. Now treat a second print in the same way, and keep on till you have all the prints in the solution. Now take hold of the bottom print, which will be, of course, the one put in first, draw it out and turn it face upwards and lay it on the top of the other prints. Treat all the prints in this way till they are all face upwards. Now pour off the soda solution and let water run freely into the dish, and keep turning the prints one over the other for about five or ten minutes. Then take up one print, and lay it face downwards in the toning bath; take up a second print, and lay it face upwards in the toning bath on the top of the other. Do not attempt to tone more than two prints at a time at first. As you get more expert you can use larger dishes and tone a dozen or two of prints at a time. Keep on turning the two prints over and over. Lift them both together and turn them over. You will see that the color will gradually begin to change, showing that the prints are toning. How long to continue toning is again a matter of experience, but there are some guides. 74 A B C of Photography, To estimate liow far toning has jn'oceeded, lift a print up by one corner and hold it up to the light, and look through it. If the high lights are brown, and the deep shadows yellow, the print if now fixed would be a bright brown. If the high lights are reddish, but the shadows are deeper, the print would be a deeper brown. If the shadows look a deep red, the print would be a broAvnish purple. And if the shadows are purplish, the print will be deeper purple. This is but a rough guide, but a very good one. We have already stated that hypo is indispensable, and that it is a good servant, but a bad master. This was said in con- nection with negative work. It applies with equal force to ]3rinting or positive work. Therefore, I strongly recommend that on no account should the fixing bath be touched till every print is toned. As soon as the print is thought to be sufficiently toned, it should be lifted from the bath, allow.ed to duain and immediately placed in Common salt 2 ozs. Water 1 pint. and there left till every print is toned, and till all the prints are in this bath. The used toning bath may then be bottled, the toning dish washed and put away, and a fresh dish got out for the fixing. A fixing solution which has been used for negatives must not be used for positives or prints. Make up a fresh one by dissolving 1/2 ounce of washing soda, and 2 ounces of hyposulphite of soda in 1 pint of water. The prints should be allowed to remain in this bath for fifteen minutes, and care should be taken that they are well covered by the solution and moved about three or four times. At the end of this time, the hypo may be pouted back into the bottle and the prints set washing. CHAPTER XVI. Gelatine- and Collodio-diloride Papers. These papers differ from the albumen paper not only in the method of manufacture, but also in the fact that gelatine or collodion is used to replace the albumen. They are characterised by giving far finer detail and more polished prints, and are also more sensitive, that is, they print quicker. The difference between the gelatino- and collodio- chloride papers in the finished results is not very great, and practically the same method of working may be adopted for both. The surfaces of both papers, particularly the gelatine, is considerably more sensitive to dirt than the all3Hmen, and there- fore greater care must be exercised in handliug them. The collodio-chloride paper is also very liable to crack if bent sharply. The papers are printed in exactly the same way as albumen paper, but the fact that they are more rapid should not be forgotten. Further from the polished surfaces v.'hich they have they are more liable to slip when examined, so care should be exercised in this respect. When printed the paper should be kept in a box as directed for albumen paper, till a sufficient number of prints have been obtained, and then before toning placed in a bath of Common salt Water 1 oz. 20 0Z3. A B C of Photography. for five minutes, waslied for five minutes and then toned. The toning bath for these papers, that at least which gives the best results, is the following; Chloride of gold 2 grs. Ammonium sulphocyanide 30 „ Boiling distilled water 16 ozs. Dissolve the sulphocyanide in 12 ozs. of the water, and dilute two drachms of the stock solution of gold (p. 71) with four ounces of water. Now add the dilute gold solution in quantities of 1 oz. at a time to the sulphocyanide, shaking well between each addition, allow^ the bath to stand for an hour and then use. The image will soon change color in this bath if the same method of working is adopted as was suggested for albumen paper, and the necessary length of toning may be judged by looking through the prints as previously described. Another bath which I can strongly recommend is the formate bath, this gives any tone from brown to purple, without, so far as my experience goes, of double tones, the only points to be observed are that the prints must be printed rather deeply and they must be treated to a salt bath prior to toning. Gold chloride 1^2 S^** Sodium bicarbonate 1 Sodium formate 7^2 S^'^* Distilled water 5 — 10 ozs. The stronger the bath, that is the less water is used, the quicker the bath tones and the more easily purple tones are obtained, on the other hand, the rich purple tones are just as easily obtained with a weaker bath by allowing it to act longer. After toning, the prints should be placed in salt and water, the toning bath put away and then the fixing bath prepared. The fixing bath is used in precisely the same way as described in the last chapter. An alternative method of treating these prints which has found much favor in the eyes of beginners, is by using what is called a combined toning and fixing bath, which is convenient as doing GelatinO' and Collodio-chloride Papers, 77 away with tlie separate and subsequent fixing. On the other hand, there is a danger that the prints when thus treated are not permanent and may soon fade. This is not a method I can recommend, but for those who wish to try it the following bath may be used : Soda hyposulphite . 4 ozs. Ammonium sulphocyanide V2 Lead nitrate 100 grs. Dissolve the hypo and sulphocyanide in the water; then add the alum, dissolved in about an ounce of boiling water, and add to the first solution with constant shaking; then add the lead nitrate also dissolved in an ounce of hot water. Heat the mixture nearly to boiling point for ten minutes, allow to cool, and filter it. Add 2 ozs. of the above solution to 2 ozs. of water, and then add 12 minims of the stock solution of chloride of gold. The prints should, after printing, be immersed in the salt solution, washed for ten minutes and then immersed in this bath, and allowed to remain till they have reached the desired color, which may be judged of as indicated above. The great danger in using a combined bath is that the prints may become what is called sulphurised owing to the acid, which is generally present in the paper, decomposing the hyposulphite. This may particularly occur if the prints are not well washed first and if the bath is used too long. No toning bath should be used for a very long time. It may be considered that two grains of gold will tone about four hundred square inches of paper: the number of prints which a bath will tone can there- fore be easily reckoned. For instance, supposing we are using half-plate paper, which measures 6I/2 ^'U — - square inches, therefore 400 31 =: 13 practically: so that two grains of gold wall tone 13 half-plate prints; other sizes can of course be reckoned in the same way. In the winter and autumn, when dull cloudy days are upon us, printing will be found to take a very long time; then the Alum Water 200 „ 10 ozs. 78 ABC of Photo g7'aphy . following procedure will shorten the duration of printing very much. The paper should be placed in the printing-frame and exposed to light till only a faint image is visible, and should then be soaked in a 10 per cent, solution of potassium bromide, made by dissolving 1 oz. of potassium bromide in 9 ozs. of water, for fifteen minutes, and then thoroughly washed in running water for ten minutes. They can then be developed with the foUow^ing : No. 1. Hydroquinone 1 oz. Sodium sulphite 1 „ Sulphurous acid 1/2 Distilled w^ater to make 40 ozs. No. 2. Potassium bromide 21/2 ozs. Liq. ammonia (.880) 180 m. or carbonate of soda 2 ozs. Distilled water to make 40 ozs. l^'or use, mix 1 oz. of Nos. 1 and 2 and add 1 oz. of water. By altering the proportions of this developer varied results may be obtained ; for instance, if harder results, that is, prints with mc^re contrast, are required, then use from half to three-quarters of an ounce of No. 1, 1 oz. of No. 2, and make up to 3 ozs. with water. For softer results, that is, with less contrast, use from 11/4 to 11/2 oz. of No. 1, 1 oz. of No. 2, and make up to 3 ozs. with "water. The prints after having beeu developed, and development should only be carried on till the image is well visible every- ^ where except the details in the very highest lights, wash well in running w^ater for at least half an hour and then tone with the sulphocyanide bath, or in the combined toning and fixing bath. There are tw^o kinds of these papers on the market, the one with a glossy or shiny surface, the other with a matt surface like ground glass. Of the tw^o the latter is usually considered to give the more artistic results. Both may be treated the same as regards printing, toning, and fixing. GelatinO' and Collodio-chloride Papers. 79 As an alternative to gold toning we may adopt platinum as the toning metal. Gold usually gives tones ranging from brown to purple, whilst platinum g-ives sepia and warm black browns. For platinum toning, printing is carried on just as for gold toning, but tlie prints sliould be treated to a batli of Common salt 1 oz. Water 20 ozs. prior to toning, then well washed and immersed in a toning bath composed of Phosphoric and dilute V2 Chloroplatinite of potash 2 grs. Distilled wuter 10 ozs. or Common salt 60 grs. Citric acid .120 „ Chloroplatinite of potash 2 „ Distilled water 10 ozs. Unfortunately, there is not much guide to the final tone by examining the prints by transmitted light. Experience alone can tell how far to carry toning, though of course the loLger the print remains in the toning bath the deeper the color. After toning the prints should be immersed for five minutes in a bath of Washing soda 1 oz. Water 20 ozs. then well washed and fixed in Soda hyposulphite 2 ozs. Washing soda ^j^ oz. Water. 20 ozs. In this the prints must remain for at least ten minutes, and then be well washed. There seems to be an increasing desire to obtain black tones on P.O.P. ; why, I can hardly see, because it is so much easier to obtain black prints by means of one of the development papers So A B C of Photography, and these can be given quite as high a surface as P.O. P. if this be desired. However for those who wish to try for these tones the following procedure may be adopted, but I may as well at the outset state that deeply printed proofs from plucky negatives are alone suitable for this method of working. Immerse the print first in Salt 1/2 oz. Sodium bicarbonate 80 ozs. Water 20 „ for five minutes, then wash well and tone either in a borax or compound bath (p. 72) till the image is a purple red, and then wash well and then toned in the phosphoric-platinum bath (see 2)revious page) and then well wash and fix. Sometimes too it is desired to obtain reddish tones with P.O. P. and these can be easily obtained by treating the prints first to a salt bath, washing well and then immersing in Uranium nitrate 1 grain. Thiosiunamine 5 grs. Water 1 oz, and then well w^ash and dry. Sometimes although the print is otherwise excellent, it is found when finished to be a little too darkly printed, and we decide it would look better if reduced. This may be effected by Lainer's Iodide reducer (p. 62) but a more satisfactory method is by using the following Uranium nitrate 1 grain Sodium hyposulphite -^/o ^2. Water 2 ozs. in which the print may be immersed after fixing till sufficiently reduced and then well washed and dried. Although somewhat unsatisfactory and entailing a considerable change of tone, P.O. P. prints may actually be inteusified with mercury, by slightly bleaching, well washing and developing with any used developer. It is sometimes considered desirable to give the polished GelatinO' and. Collodio-chloride Papers, 8i papers a very high surface, and this can be effected as follows. Procure a sheet of plate-glass of fair size; this can be obtained very cheap from any Plate-glass Insurance Company. Make a solution of Yellow wax 25 grains. in turpentine 1 oz. Melt the wax by placing it in a cup or bottle, shredding it up fine first, and standing the vessel either in hot water or in the oven. When the wax is quite melted, remove the vessel from the water or oven, and add the turpentine. Clean the plate-glass well by rubbing it with a damp cloth, polish it quite dry; then pour a little of the above solution on to the middle and rub it all over with a soft linen pad, and keep on rubbing till the best part of the solution is removed an-d it shows no streaks; now leave it for ten minutes to dry. A squee2:ee will be required; this is a strip of rubber fastened by the edge length- • ways between two strips of wood fixed to a long wooden handle ; any dealer can supply this little device for a few pence. The well-washed print should be placed in a tray full of clean water, and the glass slipped into the water underneath the print. The print must now be brought picture-side downwards into contact with the glass, held there by one finger, both raised together and then lifted out of the dish. The glass bearing the print should now be laid flat on a table, and the squeegee passed firmly and steadily all over the print from every direction, till on lifting the glass up and looking through it, no air bubbles are seen between the print and glass. They can readily be detected if they exist. The print when squeegeed down to the glass may be left to dry, which it will do in an hour or two if left in a warm place. When thoroughly dry, a clean penknife may be passed under one corner, this corner taken hold of by the fingers, and the print steadily and gradually pulled off the glass, when it will be found to have a polish like the glass itself. CHAPTER XVI T. Plain or Salted Smooth and Rough Papers. There is a fashion in photography as in everything else al- most, and for some years there has been a growiug tendency to use what are called plain or salted papers, either with smooth or rough surfaces. These papers have no polished surface, merely that of the paper itself, and almost any good paper, particularly the drawing papers, may be prepared, and will give, when properly treated, very pleasing results. They are not difficult to prepare, and give artistic results, particularly with th© platinum toning baths. The paper must first be * salted', that is, coated with a solution of some chloride salt, and to prevent this sinking into the paper a little arrowroot is added; the salting solution is prepared as follows : Rub the arrowroot up in a cup or basin with about one and a half ounces of the water, enough water being used to make a fairly thick cream. Fifteen ounces of water should row be boiled and poured, in an even quick stream, into the arrowroot and water, stirring well the whole time; the liquid will then Chloride of ammonium Sodium carbonate Citric acid (crystals) . . . Arrowroot , Distilled water 120 grs. 240 „ 60 „ 200 „ 20 ozs. Plain or Salted Smooth and Rough Papers, 83 be sliglitly thicker, but milky-lookinoj. The whole should now be transferred to a clean sauc( pan, preferably an enamelled one, and heated till it becomes clear. With a little care this may be done without actually making it boil. Whilst this solution of nrrowroot is cooliug, add the ammonium chloride, citric acid, and carbonate of soda to two ounces of w^ater, which should be placed in a half-pint measure or gallipot. A large measure should be used as the mixture effervesces, and therefore if a small measure is used it may boil over the top. When all the salts are dissolved, the solution should be placed in the oven or near a fire, and left for about a quarter of an hour, and then added with constant stirring to the arrowroot, and the whole made to measure 20 ounces. The paper to be prepared should be pinned by drawing-pins to a flat board, and is then ready for the solution to be applied, for which purpose we can use a brush, though the best thing is what is called a blanchard brush; this can be made very easily. Procure a piece of hard wood, such as oak or teak, about six inches long and two inches wide and I/4 inch thick, and varnish it well. Instead of wood a piece of plate-glass may be used, of the same size, grind the sharp edges off with a file or on any convenient stone, such as a paving stone or the steps. Now procure some swansdown calico, six inches wide, and about eight inches long. Double this so that the fluffy side is out- side. Procure a piece of stout celluloid, such as is used for the i-upport of emulsions, instead of glass. Bend this into an arch, place over it the sw^ansdown calico, then fit it on to the wood, and pass round the whole a stout india-rubber band so that \i forms a convenient little apparatus. There is one point which should not be forgotten, and that is that almost all papers have a right and a wrong side. To tell the right side, hold the sheet of paper up and look through it, and turn it about till you can see the water-mark the right way up. The side nearest the eye is the right side, and a small pencil-mark should be made in one corner of the sheet, on the wTong side. We have made our solution and brush, and pinned the paper 84 A B C of Photography. right side up on the board, and are quite ready to salt. Pour about four ounces of the salted arrowroot solution into a pie dish, soup plate, or a clean photographic dish. Dip the blan- chard brush into the solution, and commencing at the top of the left-hand side of the paper, draw the brush firmly but lightly across the paper; when you have reached the end redip the brush and work from ri^?ht to left. Do not be too long about this, with a little practice it will become very easy to rapidly and evenly coat the paper. When all the sheet has thus been gone over, turn the board so that its longer side is at right angles to what it was before and then with a light circular motion go all over it with the brush so as to even out any marks and make the coating quite regular. At the end of a few minutes, the solution will begin to penetrate into the paper and the surface appear less shiny. At this stage the paper should be hung up by wooden American clips fastened to a string or line hung across the room, and allowed to dry. It will be as well to begin and practise with small sheets of paper first, and as experience is gained to salt larger ones. The paper should be hung up to dry in a warm room, the warmer the better, and left till quite dry, when the sheets may be taken down, laid one on top of the other, wrapped in clean white paper, and kept under a weight. The paper in this condition will keep for years. For sensitising the paper, that is, making it sensitive to light, a solution of silver nitrate and citric acid is used, prepared as follows : 1. Citric acid 125 grs. Dissolve in Dissolve. Mix the two solutions and label "Silver Citrate Solution. — Poison." It must be remembered that silver nitrate will blacken the fingers, table cloths, or, in fact, anything that it touches. Should Distilled water. 2. Silver nitrate.. . Distilled water 21/2 oz. 300 grs. 21/2 oz. Plain or Salted Smooth and Rough Papers. 85 a spot be spilt on any table clotb, it should be immediately covered with dry kitchen salt, and a drop or two of water dropped on to it, allowed to remain for a miuute, and then the spot dipped into a clean fixing bath. To sensitise the paper, it is pinned as before to a flat board, the salted side up, which, of course, can be told by the pencil- mark not being on this side. Some of the silver solution should now be poured on to it at one end, the quantity of solution depends a good deal on the size of the paper, but for a sheet measuring about 480 square inches, about three-quarters of an ounce of the above silver solution will be required. From this statement it will be easy to reckon how much will be required for any given size of paper. To distribute the sensitising solution, a blanchard brush may be used as for salting. A fresh one should be made wath only one thickness of calico, and this should be well washed in distilled water before use, and wrung out nearly dry. Spread the silver solution in exactly the same way as for the salting solution, and dry the paper in the same v^ay, only remember that now the paper is sensitive to light and therefore artificial light or day- light subdued by dark blinds should be used. A good plan is to sensitise the paper at night and use it the next day. The sensitised paper will not keep long, therefore a large quantity should not be sensitised at once After sensitising and drying the paper, it should be rolled up, sensitised surface inside : and here note that the paper will now be affected by dirty fingers. If more than one or tw^o sheets are sensitised, it may be rolled up, wrapped in white paper and then in thick brown; but a far better plan is to immediately cut it up to the sizes required and keep it in a plate box with a bit of glass on the top of the paper to keep it flat and tight. Another very good way to keep the paper is to cut up blotting paper, the pure white thick variety, to the same size, soak this for two minutes in solution of carbonate of soda and then dry, and when putting the silvered paper into a box, put between each sheet of sensitised paper a sheet of the soda paper. Printing on plain paper, requires but little difference in mani- 86 A B C of Photography, pulation to the ordinary commercial papers ; thougli a little deeper printing is advisable. It may be treated in exactly tbe same way as suggested for albumen paper prior to toning, but all the toning and fixing balhs must be just half the strength, that is, after having made up one of the toning baths suggested for albumen paper, an equal quantity of water must be added. This paper gives excel- lent results with the platinum toning baths suggested on page 79. The subsequent operation of washing is precisely as indicated for the other papers. CHAPTER XVIIL Platinotype Paper. Tkis paper may be considered to stand midway between the printing-out papers and those requiring; development. For although a faint image can be seen alter exposure to light, the paper must be treated with a developer to bring the image out in its full beauty. There are three kinds of paper; one with which the image is printed out, another requiring a hot developer, and the third a cold developer. The printing- out platinotype paper is somewhat easier to use than the others, but does not keep quite so well, though it can- not be said that any of them keep really well. They should all be kept in what is called a calcium tube, which is a tin tube, at one end of which is a chamber in which calcium chloride (anhy- drous) is placed, this chemical is very greedy for water and readily absorbs any moisture., which may get into the tube when it is opened. The printing- out platinotype paper should be left for some time in a damp place after removal from the calcium tube, in order to allow it to absorb some moisture. A very good method of doing this is to take an empty plate box, lay in the bottom of it a piece of damp blotting paper, and on this, face upwards, the platinum paper. On the lid of the box pin another piece of damp blotting paper, and place for a few minutes near afire, for instance on the mantelshelf. 88 A B C of PJiGtography, The paper is placed in the printing-frame like ordinary silver paper, and exposed to diffused light till the image is plainly visible, when on removing the paper from the frame and holding it in the stream of steam as it issues from a kettle the image will turn a rich velvety black. As an alternative method the joaper may be breathed on whilst in the printing- frame, but this method is certainly not to be recommended as it may lead to a deep staining of the negative which nothing will eradicate. As soon as the print is well developed, it should be placed in a bath of hydrochloric acid — 1 drachm, water 30 ounces — kept on the move for five minutes, and then transferred to a second oath of the same strength for the same time, and finally to a third bath, after which it may be washed well in running water and allowed to dry. The hot-bath platinotype paper, as it is usually called, is prepared not only to give black tones, but also sepia tones. It must be very carefully preserved from damp, and it is even a good thing to w^arm the back of the printing-frame thoroughly, and to place between the back and paper a sheet of thin (about one-sixteenth inch thick) india-rubber. The exposure to light is continued till a distinct grey image is seen with all the details on the greenish yellow ground of the prepared paper. After printing, if the paper is not to be developed at once, it should be put back into the calcium tube, till a sufficient number of prints have been obtained. The developer is composed of Neutral oxalate of potash . 1 lb. Distilled water 31/2 pints; or Neutral oxalate of potash l/g lb. Phosphate of potash V4 lb. Distilled water 31/2 pints. To make the developer hot, it is advisable to purchase an iron dish, or even a good tin baking- dish may be used. This should be supported on an iron tripod, which may be obtained from almost any dealer or chemist, it being in common use for Platiiioiype Paper, 89 chemical work, and underneatli the dish should he placed a spirit lamp or Bunsen gas-burner. Having filled the dish to the depth of about one and a half to two inches, place on the tripod and light the lamp, and place it underneath. A thermometer will be required; a proper chemical thermometer, with the graduations marked on the glass, may be obtained for about two shillings, as one not graduated to a temperature over 212° F. (—100° C.) will be required. Of course, any thermometer which is fastened to a porcelain, not wood or metal, base may be used. The thermometer should be placed in the dish and moved about till the temperature registers from 120° to 160° F. (= 50° to 75° C). The print should then be taken with the two hands at opposite sides, usinu; two fingers only, and one eud immersed right in the solution, and the print drawn rapidly through the solution, removed, and turned over. The image will immediately be seen to be rapidly gaining in blackness, and as soon as deep enough it should be immediately immersed in the dilute hydrochloric acid mentioned above for the printing-out paper, and treated exactly in the same way as that. The temperature of the developer has been stated at from 120° to 160° F., the idea of this is as follows. Suppose that one finds that after one has developed the first print of a batch that it is over-exposed and too black, without any pure whites, when developed in a bath of 160° F., we can by reducing the temperature to 120°, or even 110°, obtain good prints even if the paper has been over-exposed. On the other hand, if we were using a bath of 120° to 130° temperature and we find our prints under-exposed, which will be known by the shadows being very black without sufficient detail in the high lights, we can by increasing the tempei'atare of the developer consider- ably improve the results. With a little practice this becomes a most valuable aid to the artistic worker — for by using a hotter solution he can obtain soft delicate results, and by using a colder solution he will obtain harder and more contrasted results even from the same' negative. The paper for giving sepia tones is specially prepared and 90 A B C of Photo gi-aphy. requires the following siiecial developer — which must be used at a temperature of at least 150° to 160° F. After development the sepia paper is treated exactly as the other black tone paper for hot development. All these papers are sensitive to light and therefore must be developed and washed in the aoid by weak daylight or lamp light. Slightly brownish tones may be obtained on the paper intended for black tones by developing in the solution just given, to which should be added mercuric chloride 30 grains. The tones thus obtained are not so satisfactory as those given by the proper sepia paper. The cold development paper is treated and printed in exactly the same way as the hot till the printing is complete, but the development is performed on either of the baths suggested for the hot bath paper, but at the ordinary temperature. With this paper, as with the hot bath, a rise or fall in tempera- ture will affect the results, so that considerable control over the results can be thus obtained. There is also another method of controlling the prints which is very valuable, which we will now proceed to describe. The paper should be laid face upwards on a sheet of plate- glass. Now obtain five saucers; in one place some pure gly- cerine: in the second, 1 part of the oxalate solution, p. 86, and 3 parts of g'ycerine: in the third, equal parts of this oxalate solution and glycerine : in the fourth, 3 parts of the oxalate and 1 part of glycerine: in the fifth, the plain oxalate solution. A large camel-hair mop varnish brush will also be required. Dip this into the pure glycerine and smear it all over the print. Then dip the brush into the second saucer, and with this solution go over the print. Possibly now some of the deepest shadows Neutral oxalate of potash. Phosphate of potash , Citric acid Potassium chloride Distilled water 11/2 oz. 240 grs. 120 grs. 80 ozs. 3 ozs. Platiiwiype Paper. 91 will begin to show. Now fill the brush from -the third saucer and go over all those parts of the print which are not showing, and lastly over the shadows. If now any portion of the print does not show up, the brush may be charged with solution from the foui'th saucer, and those parts which do not show brik-hed over, and then finally, if necessary, the plain oxalate solution may be used. If a little care is used absolutely no lines of demarcation will show, and this process places an enormous power in the bauds of artistic workers to modify the results. This paper, by whichever method it is developed, is sub- sequently treated exactly like the other kinds. It frequently happens that a platino-type print is developed too much or printed too deep, and unfortunately it is extremely difficult to reduce. The best method of doing this is to obtain two ounces of ordinary bleaching powder or chloride , of lime, mix this with 8 ozs. of water, and filter the solution into a bottle. The print to be reduced should be placed in a clean dish, flooded with the solution and allowed to soak for a few minutes; half an ounce of ordinary household vinegar should now be measured out, the chloride of lime solution poured from the dish into the measure, the mixture immediately poured back over the print, and the dish rocked till the print is sufficiently reduced, when it should be well washed in water and dried. Our print may, on the other hand, be too weak and pale and then we can intensify it. One method is by using s lver nitrate, and although I give the formulse and necessary working direc- t ons, I cannot recommend it so strongly as the second process described hereafter. Two solutions are required. 1. Hydroquinone 2 grs. Citric acid 20 — Distilled water 1 oz. 2. Silver nitrate 48 grs. Distilled water 1 oz. The prints, after treatment with acid and well washing, should 92 A B C of Photography. be placed in a clean dish. Ten drops of No. 2 should be added to 1 oz. of No. 1, and tke mixture, which will be thick and cloudy, immediately poured over the prints, and the dish rocked. The precipitate will gradually turn black, but before this takes place the print will be seen to gradually gain in depth, and at the desired stage it should be removed from the solution, well washed, and placed for five minutes in a fixing solution of hypo 2 oz. and water 20 ozs. and then well washed. A better method is that suggested by Dollond, for which four solutions are required. No. 1. Gold chloride 15 grs. Distilled water 71/2 drachms. Dissolve and add a small piece of prepared chalk about the size of a hazel- nut, shake w^ell, filter, and add one drop of strong hydrochloric acid. No. 2. Pure glycerine. No. 3. Sodium sulphite 1 oz. Distilled water 10 ozs. Metol 50 grs. No. 4. Potassium carbonate 1 oz. Water 10 ozs. The prints, after treatment with acid and washing, should be soaked, in water for two or three minutes, then laid face upwards on a sheet of opal glass and the superfluous water blotted off with some clean white blottiug ]mper. Then a brush charged with pure glycerine should be passed all over the sur- face. Now a few drops of the gold solution should be dropped on to the print and with the brush everily and quickly worked over the whole of the surface. The print will gradually gaiu in depth aud richness of colour, and if this solution is allowed to act long enough will assume a blue black colour. When the Platinotype Paper. 93 desired depth of colour is reached the print should be well washed with water, and a mixture of equal parts of solutions 3 and 4 sponged over both back and front and allowed to act for about five minutes, and then the prints thoroughly well washed and dried. Platinotype prints may also be toned with uranium to obtain brown or even reddish brown tones. Make the following solutions : No. 1 Uranium nitrate 48 grs. Glacial acetic acid 48 minims. Water 1 oz. No. 2. Potassium ferridcyanide 48 grs. Water 1 oz. No. 3. Ammonium sulphocyanide 240 grs. Water 1 oz. Tor use, add 10 minims of each solution one after the other to 2 ozs. of water, flow the mixture over the print in a clean dish, and rock till the desired tone is obtained, when the solution should be thrown away, and the print washed and dried. Blue tones may also be obtained as follows: No. 1. Ammonia iron alum 48 grs. Hydrochloric acid 48 grs. Water 10 ozs. No. 2. Potassium ferridcyanide 48 grs. Water 1 oz. No. 3. Ammonium sulphocyanide 240 grs. Water 1 oz. For use, add to 1 oz. of water, 5 minims of No. 1, then 2 94 A B C of Fhotography, minims of No. 2, and then 5 minims of No. 3. The solution should be of a red colour and is used precisely as tlie last solution. Should the tone be unsatisfactory by either of these methods, soaking the print in liq. ammonia 1 oz. and water 20 ozs. will entirely remove it, and the print after washing, can be treated afresh. It is advisable after these toning processes to wash the prints in hydrochloric acid 1 drachm and water 60 ozs. instead of plain water. Another method of oblaining warm tones, especially with the cold bath pktinotype paper, has been suggested by Mr. Peebles Smith of U.S.A., and for it the following solutions are required. A. Potassium Oxalate 4 oz. Distilled water 16 ozs. B. Cupric chloride 124 grs. Distilled water 16 ozs. C. Mercuric chloride 1 oz. Distilled water 16 ozs. D. Lead acetate 32 grs. Distilled water 4 ozs. Mix 3 ozs. of A., with 1 oz. of B., stir well and add 1 oz. of C. and add I/4 oz. of D. and heat till any deposit is redissolved. Filter the solution and place in an earthenware dish and heat to 80° to 85° C, The prints should be drawn through the warm solution, laid face upwards on a sheet of glass to gain the desired depth of color, and then washed in acidulated water. Variation in color may be obtained by increasing or decreasing the amount of mercuric chloride. CHAPTER XIX. Bromide Paper. Paper coated with an emulsion, similar to that used for dry- plates, but of a somewhat slower speed is called Bromide Paper. It is extremely convenient, as by its aid we are able to obtain rapid proofs of any negative and work during the dull days of winter or at night, daylight not being necessary, in fact a dis- advantage rather than otherwise for exposiug. Bromide paper is extremely sensitive to light, and therefore the packets must only be opened in the dark room. Though here we need not use such a deep red light, in fact a bright orange will 'be found not only quite as safe, but far more convenient as enabling us to see better what we are about. The paper is placed in the printing frame in contact with the negative, and the back of the frame fastened down. There is frequently some little difficulty with beginners in telling which is the film or coated side. The simplest plan of telling this is to take a piece of paper from the packet and lay it on the open hand; it will immediately begin to curl up witii the coated side inwards, this is the side which should be placed next the film of the negative. The paper may be exposed to any artificial light, such as lamp or gas light, at a distance of eighteen to twenty-four inches. The du' ation of exposure will, of course, vary with the brightness of the light, the rapidity of the paper, and the colour and density 96 A B C of PJiotography . of the negative. There is no true guide to the exposure, experience alone, as with dry plates, can decide ; but the following dodge, suggested by Dr. Herklots Vos, will be found au approximate guide. Lay down on a shelf or bench a six-foot inch-tape, with the 72-inch mark exactly parallel with a No. 5 Bray burner, which should be turned up to its fullest extent without flaring. Now procure a piece of flashed opal glass, about half-plate size; the opal glass must be ground, or 'smoothed', as it is called on the opal side. The opal glass is placed in contact with the film of the negative ; the latter being next the operator. The two should now be held up between the eye and the gas burner, at the full length of the inch tape. Now examine the image and gradually approach the negative nearer to the light till all the details, such as the markings on a brick wall, or the trunk or leaves of a tree, just become visible. Note the distance between this point and the end of the inch-tape, and give an exposure corresponding in number of seconds to number of inches, at a distance of two feet from the gas burner — for instance , the details of a negative became visible at a distance of 30 inches from the six-foot mark, then that particular negative required thirty seconds exposure at a distance of two feet from the burner. There are various kinds of bromide paper in the market, on smooth thin paper, on smooth thick paper, and rough thick paper, as well as some which has a brilliant enamel surface like ge latino-chloride paper, and another which has a surface like platino-type paper, and which is usually called platino-bromide paper. There are several different speeds of paper ; and as some guide to the beginner we may state that for a somewhat thin soft negative, a slow paper should be exposed at some distance from the light, whilst for a very dense or harshly contrasted negative a rapid paper should be exposed near the light. A slow paper under-exposed at some distance from the light will give increase of contrast, whilst a rapid paper over-exposed near the light will give reduced contrasts. After exposure the print has to be developed, and for this purpose we may use either the old-fashioned ferrous oxalate, which for bromide work has been first favourite for many years. Bromide Paper. 97 or one of the newer developers. Pyro alone is unsuitable for bromide paper on account of its great staining po^vers. Ferrous Oxalate Developer. No. 1. Neutral oxalate of potash 1 lb. Distilled water to 3 pints. No. 2. Ferrous sulphate V4 lb. Sulphuric acid 10 drops. Distilled water to 10 ozs. To make the developer, add quarter of an ounce of No. 2 to one and a half ounces of No. 1. and add about 20 drops of a ten-per-cent. solution of potassium bromide (see p. 39). It will be noted that it is directed to add No. 2 to No. 1, and not No. 1 to No. 2, this is very important, otherwise the mixture will be all thick and cloudy and be spoilt. The print after exposure should be laid face upward in a clean dish, and the developer flowed over it in one wave, and the dish rocked. The picture will gradually appear, and development should be allowed to continue till the print is dark enough. Previous to commencing development, the following solution, which is called the clearing solution, should be made up : Glacial acetic acid 1 drachm Water 32 ozs. A lot of this solution should be made up, it costs very little and plenty will be required. As soon as the print is sufficiently developed, it should be immersed in the above clearing bath, without washing, and allowed to remain for five or ten minutes. The solution should then be thrown away and fresh poured on to the print. A very good way of working, when more than one print is required from the same negative, provided, of course, that the correct exposure has been found as suggested above, is to expose as many pieces of paper as prints are required: placing 98 A B C of F/iotography, eacli piece of paper as exposed in an empty plate box. Arrange four dishes in a row, reserve the first for the developer only, and fill the other three with clearing solution. Develop one piece of paper and place in the first clearing bath, and then develop the next piece; before development is quite complete, remove the developed print from the first to the second clearing bath, this frees the first dish for the paper in the developing dish, from w^hich it may be taken as soon as sufficiently developed and placed in the first clearing bath. A third paper may now be developed, the first piece removed to the third clearing bath, and the second piece from the first to the second bath, leaving the first free for the third print. After the first clearing bath has been used for three pi'ints it should be thrown away, and the second dish moved up in its place, the third dish moved up into the second place, and the empty dish placed third and filled with clearing solution. By working in this way consideralile saving of time may be effected and the developer may be used for four prints before being thrown away. As soon as all the prints have been developed and all the prints are in the clearing baths, these latter should be emptied, refilled with the clearing solution, and the dishes well rocked, then, and then only, the prints may be washed — washing after clearing should be thorough, at least half an hour in running water and then they can be fixed in a plain hypo bath, made by dissolving 3 ozs. of hypo in a pint of water. In this bath the prints should remain for at least fifteen minutes and then be thoroughly washed and hung up to dry. When using ferrous oxalate there is considerable danger of the prints becoming stained, and extreme care must be taken not to touch the prints except at one extreme corner, and the fingers must be absolutely clean. For this reason and because of the necessity of using the acid clearing baths, the newer developers have grown into more general favour with beginners of late. The following formulse will be found very satisfactory. Hydroquinone Developer No. 1. Hydroquinone 154 grs. Bromide Paper. 99 Sodium sulphite 1 oz. Sulphurous acid 1/4 oz. Distilled water to make 20 ozs. No. 2. Washing soda 3 oz. Caustic potash 154 grs. Potassium bromide 20 „ Distilled water to make 20 ozs. Mix half an ounce of each solution and add three ounces of water. There is only one disadvantage with hj^droquinone, and that is the gi'eat tendency to give rusty black and not pure black tones. Eikonoo-en Developer. No. 1. Eikono(;ep. 50 grs. Sodium sulphite 1 oz. Distilled water to make 10 ozs. No. 2. Washing soda 1 oz. Caustic potash 56 grs. Potassium bromide 20 Distilled water to make 10 ozs. Mix half an ounce of each solution and add 1 oz. of water. Eikonogen and Hydroquinone. No. 1. Hydroquinone 40 grs, Eikonogen 120 Sodium sulphite 1 oz. Citric acid 20 grs. Distilled water to make. . .'. 20 ozs. No. 2. Potassium bromide 5 grs. Washing soda. . 60 „ Caustic soda 30 „ Distilled water to make 20 ozs. 100 A B C of Photography. Mix half an ounce of each and add 1 oz. of water. This developer gives more satisfactory results than either of the two previous* Metol Developer. No. 1. Sodium sulphite 2 oz. Distilled water 20 ozs. Dissolve and add Me-tol 100 grs. Potassium bromide 12 No. 2. Potassium carbonate 2 oz. Disiilled water 20 ozs. For use mix in equal parts. This developer gives exception- ally fine results and is the one I strongly recommend. Amidol Developer. No. 1. Sodium sulphite 2 ozs. Distilled water to make 20 „ No. 2. No. 1 solution 1 oz. Water 5 ozs. Amidol 20 *grs. Potassium bromide 1 gr. Not more solution should be made than can be used in one day. No. 3. No. 2 solution 1 oz. Water 4 „ Place the print in a dish and flood with No. 3 solution, and rock the dish. Allow development to continue till the shadows are well out, and then pour off this solution and apply No. 2, and allow development to proceed till the print is black enough. This, though a little troublesome, is a very satisfactory method of working. No acid clearing bath is required after any of these develop- ers, the prints may therefore be rinsed with water when suffi- ciently developed and then fixed in the acid fixing bath. CHAPTER XX. Warm Tones on Bromide Paper and Alpha Paper. Tired with the all-prevailing coldness and blackness of bromide prints, the devotees of photography some little time ago were much struck with a process of toning bromide prints to a rich -warm brown by means of uranium, and whilst not very difficult it requires some little care. The print must be thoroughly well washed and freed from hypo by treatment w4th Anthion (see p. 56). If tbe print has been dried it should be soaked in water till soft. Two solutions are required. No. 1. Uranium nitrate 100 grs. Glacial acetic acid I/2 oz. Distilled water 5 ozs. No. 2. Potassium ferridcyanide. 100 grs. Distilled water , 5 ozs. Por use mix in equal parts and flow over the print, rocking the dish till the desired tone is obtained. Then wash in the acetic acid clearing bath mentioned in the last chapter, and after a final rinse in plain water allow to dry. An excellent method of obtaining warm tones on bromide paper is by the use of a copper toning process for which we require the following solutions: 5 I02 A B C of Photography. A. Copper sulphite 1 oz. Water 10 ozs. B. Potassium citrate 2 „ Water 10 „ C. Potassium ferridcyanide 1 oz. Water 10 ozs. For use mix 1 oz. of A., 7 ozs. of B. and ^j^ oz, of C. and immerse the fixed and well washed print to remain in this till the desired color is reached and then wash and dry. Bromide prints may, if too dark from over-exposure or over- development, be reduced by any one of the methods suggested for negative work, though Belitzski's reducer will be found the most convenient. Under-developed prints may also be intensi- fied by one of the negative intensifiers, Monkhoven's, or the method with re- development by a developer will be found to yield the most satisfactory prints. Alpha paper is somewhat similar to bromide paper, in that it must be manipulated by a red or orange light and requires development to produce a visible image, It, however, not only requires a much longer exposure than bromide paper, but gives a warm-coloured image, ranging from a bright yellow to a rich violet black. For some reason or other, however, it is not a general favourite, possibly thts being due to the fact that uni- formity of tone is a little difficult to attain if care is not exercised. The paper is sold, cut to size, in p'ackets, and a sheet of papers should be placed in contact with the negative and the printing frame fastened down. To ensure even-toned prints from the same negative every item must be carefully attended to. About six inches from a No. 5 Bray burner make a distinct pencil mark, on a shelf or board: the printing frame must be placed close up to this mark for every exposure, whish will vary from two to three or four minutes. Expose as many pieces of paper as you require prints, giving each piece exactly the same exposure: timing the exposure by means of a watch. Place the exposed paper in an empty plate box till sufficient has been exposed, then prepare the following developer. Warm Tones on Bromide and Alpha Papers, 103 Hydro qui none 20 grs. Ammonium carbonate 1 oz. Potassium bromide 10 grs. Sodium sulphite 1 oz. Distilled water to make 20 ozs. Place the prints in a dish, flow over with this developer, and rock the dish till the image appears sufficiently strong; then transfer the prints to a dish of clean water and wash for at least lialf an hour in running water, at the end of which time they may be treated with the following combined toning and fixiag bath : Distilled water 20 ozs. Hyposulphite of soda 5 Acetate of sola 1 oz. Ammonium sulphocyanide I/2 „ Chloride of gold 8 grs. l)i>sulve the ingredients in the above order and allow the bath to stand for forty-eight hours. Immerse the prints in this one at a time, and &ee that they are well-covered by the solution. They will tirst of all turn a bright yellow and then gradually darken in colour, and may be removed at any desired stage, it being remembered that when washed and dry they will be a little darker and bluer in color than when wet. After toning they should be washed in running water for at least two hours, then dried and mounted, or may be squeegeed to polished plate glass or ground glass as described for gelatino-chloride paper, to obtain either a highly glazed or rough surface. Recently another class of development paper has been introduced which has the peculiar property of not requiring any dark room at all, for it may be developed in gaslight, as long as the dish is kept about 3 feet from the naked light or at least not unduly exposed to it. These papers are known under various trade names such as Velox, Gravura, Dekko, Gaslyt etc. but the method of using them is practically common to all. They naturally require very much longer exposures than bromide 104 A B C of Photography. paper, so mucli so tliat at a distance of from 6 to 12 inclies from a gas flame it runs into two or three minutes. Far preferable, however, to gas is the use of masjnesium ribbon, as it is more certain and constant. One advantage which is possessed by these papers is that by increasing the exposure and modifyiug the developer, various tones or colours ranging from black to bright yellow may be obtained. Briefly the directions are as follows: for black tones, expose to 2 ins. of magnesium ribbon at a distance of 4 ins. from the printing frame, and develope with A, Hydroquinone 100 Q;rs. Sodium sulphite 1 oz. Citric acid 25 grs. Potassium bromide 20 „ Distilled water to 20 ozs. B. Caustic soda 90 grs. Water to 20 ozs. Fur use mix in equal parts. For brown tones, expose to 3 ins. of magnesium ribbon and develope with 1 oz. 1 „ 60 minims. The third solution or C. is prepared thus: Ammonium bromide 120 grs. carbonate 120 „ Water to 10 ozs. For purple tones expose to 4 ins. of magnesium ribbon and develope with Solution A 1 oz. B 1 „ C 1/4 .. Solution A B C Warm Tones on Bromide and Alpha Papers. 105 Tor red tones expose to 8 ius. of magnesium ribbon and develope with Solution A 1 oz. B 1 „ C 3/^ „ By increasing: tlie magnesium to 12 ins. and tlie proportion of solution C. to 1 oz. yellowisli tones are obtained. The after treatment of fixing and washing are the same ns for bromide paper. CHAPTER XXI. Carbon Printing. This is one of the most beautiful and the most permanent of all photographic printing processes, and is based on the fact lhat gelatine, when impregnated with bichromate of potash, becomes insoluble in hot w^ater after exposure to light. By mixing various coloured pigments with the gelatine, it is obvious we can obtain prints in various colours, and the usual commercial papers are sold in the following colours; photographic purple, standard brown, engraving black, sepia, red chalk, green or blue. It is not usual to speak of carbon paper, the technical term for it being carbon tissue, and it may be obtained either in a sensitive or insensitive condition, and I should strongly advise the beginner to purchase it already sensitised : it is far less trouble, it costs no more than the non-sensitised, but has the disadvantages of not keeping longer than a fortnight. It should also be bought cut to size. If bought unsensitised, it must be immersed for thirty seconds in summer and forty-five in winter in Potassium bichromate 1 oz. Distilled water 20 ozs. Liquor ammonia ('880) 5 drops The paper after immersion should be hung up to dry in a warm place, so that it will dry in about eight or ten hours. It must not be forgotten that the paper becomes sensitive on drying, and therefore this operation must not be performed in daylight, or at least only in very weak daylight. The negative to be used for carbon printing must be provided with what is known as a 'safe edge'. This may be a thin coating of black varnish ; but preferable to this are the ordinary orange lantern-slide binding strips, which can be obtained from any dealer, in length about 14 inches and about half an inch wide. One of the strips should be wetted and stuck on to the glass, not the film, of the negative all round. If the full Carbon Printing^ 107 width of the strip is too great it may, of course, be cut down. Any ordinary printing frame may be used, but it is advisable to increase the pressure by inserting four or five thicknesses of thick white blotting paper, or preferably, one or two thicknesses of an ordinary photographic mount cut to size. The progress of printing cannot be observed and therefore we must use what is called an aetinometer. These can be pur- chased commercially in various patterus, but one can very well be made with very little expense at home. Cut a strip off an old quarter-plate negative glass, from which the film ha^ been cleaned, half an inch in width. Now procure some thin tissue paper and cut in strips of the same size, lay one strip on a flat surface, give the glass strip a thin coating of ordinary starch paste, and press firmly and evenly on to the tissue paper. Then treat the glass and tissue paper with paste, and press on to a second piece of tissue paper, but not right up to the end of the first piece ; that is to say, the second piece of tissue paper must be just half an inch shorter than the first. This operation must be repeated till eight pieces of tissue paper have been used, each piece being just half an inch shorter than the preceding one. When finished we shall have an instrument which will present somewhat the appearance of Fig. 13. — Griass. Tissue Paper. Fig. 13. This is, of course, an extremely exaggerated section of our little aetinometer. A thin strip of sheet brass should now be obtained, the same size as this glass, and the sharp edges of the glass and brass should be taken off with a file. To complete this little device we merely want a stout indiarubber band or two, twisted once or twice round each end of the brass and glass, to keep them fairly tightly together. Between the brass and tissue paper, for this should be inside to keep it clean, should be placed a strip of albamenized or gelatino-chloride paper, when we want to print our carbon tissue, and this little aetinometer should be placed on the side of the printiDg frame in which the tissue is io8 A B C of Photography, placed. As we liave already stated the image on the carbon tissue is invisible, and therefore we use the actinometer as a guide to the duration of priuting. Place the frame and the actinometer in a bright light, not sunlight, and at intervals examine the actinometer strip, and when the fifth or sixth strip under the tissue paper shows a decided tinge, remove the carbon tissue for development. There cannot, of course, be any sure guide given as to the neces?ary duration of exposure to light, but carbon tissue will print in about one- third the time of albumen paper and in about the same time as gelatino-chloride paper; obviously one negative may require five tints of the actinometer, another one six, or even seven or eight. Should it be found that the tissue paper does not stop out sujSicient light, and that, when the eighth strip is plainly visible, the carbon tissue is not sufficiently printed, a piece of ground glass may be placed over the actinometer, this will reduce the light and, of course, prolong the exposure. At first it is advisable to develop each print, or at least one print from each negative, so as to make sure that the exposm'e is correct, and having found this and noted that the actinometer printed, let us say, to the seventh strip, we should call this a seven-strip negative, and in the future would merely have to expose the tissue under this negative till the seventh strip ap- peared to ensure correct exposure. Now it has been stated that the action of light was to render the gelatine insoluble in hot water, and it must not be forgotten that the light acts on the surface first, so that to develop the tissue we have to wash away the soluble gelatine which lies next to the paper. To do this we have to strip the paper off, and it is obvious that if we merely pla^e the tissue in hot water we should have the picture floating about in the water. We therefore use a support, this may be either paper, wood, glas& or metal, and this is one of the advantages of the carbon process, that we can transfer our print to almost any material. "When we print from a negative in the ordinary way on silver- paper, we obtain a picture which is as we saw the object in nature, but suppose we turn our silver print over aLd look at Carbon F?^ in ting. it ttrougli tlie paper, we shall find that Ihose ohjects which were on the right hand have now come on the left, and vice versa, that is to say, the picture is reversed as regards left and right. Now we turn our carbon tissue over to develop it, hence the picture will be reversed as regards right and left. For some subjects this, of course, will not matter; for instance, in a portrait, where the he, d and shoulders only are seen, and also in pure picture making where we do not intend to represent a view of any particular object or place. On the other hand, it will be absurd to represent anyone as left-handed, or to show a married lady with her wedding ring on her right hand, or a view of the Houses of Parliament or any other well-known building the wrong way round. It is therefore necessary to retransfer the picture. When the tissue is placed on to a support, de\eloped and not transferred, it is called the single transfer process, if retransferred, the double transfer process. "We shall proceed to describe the single transfer process first. Special single transfer paper may be obtained commercially from the makers of carbon tissue, and at first this should be used. For developing we require four dishes, a scraper squeegee, a piece of plate-glass or stout zinc, single transfer paper and plenty of hot water. The dishes should be either porcelain, zinc or enamelled iron, bat cheaper than these and quite as effective are ihe ordinary baking tins, which can be obtained at any ironmongers; they should be bought as deep as possible and large. For instance, for half plate they should be not smaller than 11X8X2 inches. We want plenty of hot water, and it is advisable to have either a kettle on a gas-stove, or else use one of the copper or brass kettles, with spirit-lamp, which are now so fashionable for the tea-table. Place the dishes in a row; in the first put cold water, in the second hot water at a tempeature of 110° F., at first a thei momcter should be used, but as experience is gained one can tell about the right temperature from the feel. The third dish is filled with cold water and the fourth reserved for the fixing solution, which in this case is not hypo, but solution of common alum 1 oz., water 20 ozs. Place a sheet of the single transfer paper into the cold water, A B C of Photography . the first dish, and allow it to soak for about three minutes or till it feels slimy to the touch. In this dish also place the exposed tissue. It will immediately curl up with the gelatine side inside J allow it to remain in the dish and it will grad- ually uncurl, and just before it has become quite straight bring it into contact with the single transfer paper, under water; slip under the two the piece of glass or zinc, which should be an inch or two larger every way than the paper; remove from the water, adjust the tissue till it is just in the middle of the paper, and then, holding it down in position with the two fingers, and with the squeegee working from the centre to the ends and sides, press into intimate contact. Do not be afraid of using the squeegee, the worst that can happen is that some of the paper will be rubbed up, but this will not matter. As soon as the paper lies quite flat remove from the zinc or glass, 2)lace on two or three thicknesses of white blotting paper, place the same number of j)ieces above, and over all place an old negative glass and a heavy weight. Leave this for twenty minutes at least. When several pieces of paper have b3ea exposed they may be made into a pile, with blotting paper intervening. For development the tissue adhering to the single transfer paper is placed in the second dish filled with hot water at a temperature of 100° to 110° F. and turned over and over till it is seen that the coloured gelatine begins to ooze out from un- der the paper. Then lift one corner and gently and steadily pull the paper ofl"; if it leaves the support without trouble all well and good, but if it still sticks, let it soak a little longer and commence by another corner. When the paper has been stripped it may be thrown av^ay as it is now useless. The print at this stage looks a dirty smudgy mess, there being absolutely no trace of an image. The hot water should now be thrown over the melting tissue by means of the hand, when the image will gradually appear in all its beauty, the still soluble gelatine mixing with the water. As soon as the print is fully developed, it should be removed and placed in the third dish filled with cold water, allowed to remain there for about five minutes, and then placed in the alum solution in the Carbon Printing. Ill fourtli dish, allowed to remain for fifteen minutes, and then well washed in water and dried. As a rule the prints dry slightly darker than they appear when wet. In order not to have reversed prints, the exposed issue is squeegeed for development to a temporary support and then trans- ferred to its final support. The temporary support may be either a specially prepared paper, zinc or glass. Beginners will find it easier to start with flexible supports, like paper, and after experience with these to use zinc or glass. The flexible tempo- rary support may be purchased from the tissue makers What- ever may be the nature of the temporary support it must be treated with the following solution: Yellow wax 36 grs. Yellow resin 12 „ Turpentine 2 ozs. Melt the wax by shredding it up fine and placing in a bottle, and the latter in an outer vessel of hot water, or an oven ; add the turpentine by degrees, shaking well, and if necessary warm the mixture by placing in hot water, and then add the resin in the form of powder. A little of this should be poured on to the centre of the temporary support and evenly distributed with a pad of linen, aud then polished with another clean pad. It is advisable to leave the temporary support when thus prepared about three or four hours before using. The final support may be paper, glass, wood, leather or any other substance which will stand soaking in water. Properly prepared final paper supports may be obtained commercially. This must be soaked in alum 190 grs., water 1 pint, for about ten minutes, and is then ready for use. The operations for double transfer do not difTer materially from those for single transfer, and are as follow: Expose your tissue in a frame simultaneously with the actinometer ; soak the exposed tissue in water till soft, place the previously waxed temporary support in water, bring them both into contact, squeegee well, allow to remain for twenty minutes, then develop as previously described. Soak in cold water, then in alum, wash well and 112 A B C of Photography , bring into contact with the final support which has been soaked in alum, squeegee well and allow to dry. When quite dry^ the temporary support may be stripped oif by inserting a penknife under one corner and pulling well. To transfer carbon prints to the rough-surface opal glass, they, may, after development and washing, be merely squeegeed down to the opal and allowed to dry, and when dry the temporary support will strip without any trouble. Polished surfaces, like glass, wood or metal, will not hold the picture well, without previous preparation, and for this the following will be found satisfactory: Hard gelatine 820 grs. Water 20 ozs. Allow the gelatine to soak for four hours and then dissolve by the aid of a waterbath. Chrome alum 12 grs. Water 4 ozs. Dissolve and add gradually to the gelatine solution, with constant' shaking, and strain through a felt jelly-bag. Heat the mixture and pour a fair sized pool on to the glass, wood or metal, and pour as much of the solution off as pos-ible, after it has run all over the surface, and then dry. When required for use it merely wants soaking^ in water for a little time. Instead of using paper as a temporary support we can use either the rough opal or a sheet of glass. In the case of opal, give it a coating of enamel collodion made of Pyroxyline 5 grs. Ether l/g oz. Alcohol 1/2 oz. Castor oil 2 drops and when set, that is, will not run, wash for ten minutes in a dish of water, then squeegee the tissue on to this and leave for forty minutes, develop and treat as usual and squeegee the final support to it. For polished surfaces, like glass, it should be treated with the above described wax solution, and then all the subsequent opera- tions are the same. A modification of the Carbon Process has sprung into somewhat Carbon Prmting, undue prominence within the last year or two and though it, which is known as the gam-hichro'nate process, is capable of yielding as fine detail and exquisite results as any other process, yet it has been somewhat ahused and has therefore fallen into some disrepute. The principle involved is that of the carbon process, hut the paper can be readily prepared at home and in any colour, on almost any paper, though for the very finest detail the single transfer paper as used in the carbon process should be used, whilst for large 2)rints, any rough drawing paper may be used, but with the exception of the transfer paper above mentioned a preliminary sizing must be given to the paper and this is best done by applying the following: Gelatine 10 grains. Water 1 oz. Methylated spirit 50 minims. Allow the gelatine to soak in the water for an hour or two and then melt by heating and add the alcohol, and allow to set and again remelt for use. Fasten the paper to be sized by means of drawing pins to a board, and with a broad brush dipped in the above solution go evenly over the whole of the surface and allow to dry. The gum solution is composed of Finest gum arabic 4 ozs. White sugar 2 „ Water 10 „ allow the gum to soak for a day or two, stirring frequently, then add the sugar and, when dissolved, strain tiirough flannel. This solution will keep well. The pigments colors are preferably the dry powders such as can be obtained from artist's colormen, and the following will give a good selection: Black — Vegetable black, lamp black, ivory black, and Chinese ink made into a thick syrup with water. Brown — Sienna, umber, bistre brown, and Vandyke brown. 114 A B C of PJiotography. Red — Burnt sienna, Indian red, Eugiish red, burnt oclire, iron oxide. Munich lake and carmine lake. Yellow — Bright ochre, chrome yellow, cadmium yellow, gamboge and yellow lake. Blue — Prussian or Paris blue, indigo or ultramarine. It is advisable to use an actinometer as in carbon printing, as the image is not visible till developed. After the paper has been sized it should be given an even coating of the gum solution given above and allowed to dry and then painted over with Ammonium bichrom te 2 ozs. Water 18 „ and again allowed to dry. It has now a faiut yellow color and is realy for the color mixture of which the vehicle is Gum arable solution as above 1 part. Fish glue (liquid) 1 „ The proportions of dry color varies slightly, but the following may be taken as typical of all. Blac-k. Gum aud fish glue 4 ozs. Ivory black 1 oz. Lamp black 160 grs. Water 20 ozs. Brown. G tm and fish glue 2 ozs. Sienna .... 1 oz. Water 5 ozs. Rub the dry colors into a stiff paste by means of a flat knife on a piece of ground glass, with a little of the gum solution, then add the rest of the solution and spread evenly by the aid of a flat brush over the paper. Any shade of color may be obtained by mixtures of those Carton Printing, ' 115 L ^ \ ii^enlioued above, for instance olive green can be made with burnt sienna, Berlin blue and a little black. To coat the paper with the color mixture fasten it by the four corners to a board, chromated gelatine siJe up, and then ]ay out color wdth a broad flat brush working from side to side and then across, and finally even out the marks of the brush with a badji;er hair softener and circular strokes, and then hang up to dry in the dark. i^fter exposure, the print is developed by floating face down- wards on cold water till no yellow color is further dissolved from the film and then pouring over the print water, in a fine stream, heated to 75^ Fahrenheit, or by allowing the print to float face downwards on water heated to the same temperature. CHAPTER XX 11. Mounting Print?. When the prints have been producecl, they will in many cases have rough unsightly edges, and will therefore require trimming before mounting on cards. Proper cutting-shapes made of plate glass can be obtained commercially, as can also trimming knives, but a very satisfactory knife will be found in a shoemaker's knife used for cutting leather, and if this be occasionally sharp- ened on a stone it will last for years. It is frequently recommended to use a board for trimming prints on, but this is unsatisfactory as the board soon gets scored in all directions with cuts which are apt to lead the knife wrong, and give irregular edges. The best thing is a piece of plate glass on which is laid an old newspaper. On this the print to be trimmed should be laid, over the print the cutting- shape, and then with a little pressure the ecle;e3 of the print may be cut cleanly oflf without blunting the knife much. . All prints should be quite dry before being trimmed. When gela- tino-chloride prints are to be squeeged down to plate or ground glass, they should be trimmed before toning. It frequently happens that a print would be much improved by cutting off some portion of it; perhaps some of the sky, or the- foreground, or part of the print at one or both sides. It is at this point, of course, that the artistic taste of the worker will come into play. A very good method of judging whether a print would be improved by cutting or trimming down, is to take two or more pieces of white paper, the same length as the Mounting Prints. 117 piint and shift tliem about over the print as it lies on the table in front of yon, till a satisfactory composition is seen, and then, the position of the papers being noted, the cutting- shape should be employed and the superfluous portions trimmed down. Very few things look worse than a print badly trimmed, partJcularly if it is not trimmed squarely. There will be no difficulty in trimming a print so that the edges are square if a proper cutting-ahape ^and a small T-square be used, or if the plate glass used for cutting has properly cut" edges square to one another. Then again it frequently happens that we have a building or a river with prominent lines, in this case the sides of the print should be trimmed so as to run parallel with these lines; it looks absurd to see a house all toppling over to one side or to see water running up hill. The paths of the amateur at the present time are far more pleasant than they used to be, now every little luxury is pro- vided for them, and far better work ought to be turned out now than years ago. Now almost every ])hotographic dealer prepares a special mountant, suitable for all classes of prints; in the old days starch paste alone w\^s used, and the operator always pre- pared it himself, and I must say that when freshly and properly made it is hard to beat. To make it, procure an ounce of starch, either a good brand like Glenfields, or preferably the powdered starch sold by the chemist. Rub this up into a stiff cream with about one ounce of water. In a clean white enam- eljed saucepan put 81-/2 ozs. of water and bring to the boil, and then immediately pour it into the starch cream, constantly stir- ring; it should now form a clear translucent jelly free from lumps, and should be transferred to the saucepan, just boiled, and then well strained through fine linen, or an old cambric handkerchief, into a jar, and ten drops of carbolic acid added. This will not keep very long, not more than a week, and for those who want a mountant alwaj^s ready to use w^hich will keep well, I should advise Le Page's clarified fish glue, which can be obtained commercially in tins. This liquid glue, mixed as required with an equal quantity of water, foi*ms an excellent and cleanly mountant. ii8 A B C of Photography. An excellent mountant whicli does not coclvie the mounts, nor sport the surface of prints, and whicli will keep for months, can be made according to a formala given by Valenta of Vienna as follows: Dextrine 90 grs. Alum 4 „ Sugar 15 „ AVater I/4 oz. 10 alcoholic solution of thymol.. 6 drops. or another easily made one is White dextrine 12 ozs. added gradually to Boiling water' 6 ozs. stir till dissolved and add 011 of winter green 3 drops. There are an innumerable variety of mounts in the market, some with cut-out apertures, into w^hicb the print can be slid, a little touch of glue at one or two corners keeping it in position; others on which the print must be stuck in the usual way. Individual taste must, of course, be the guiding spirit as to which is the most suitable style of mount, The only advice I can give is to avoid all strongly coloured mounts, or those with bright coloured lines on them, particularly the kind known as Oxford mounts; they are very ugly and usually distract the eye from the picture, which should, of course, be the principal thing. To mount the print: first of all lay it on the mount till it appears to be in its right place — many people prefer to mount their prints centrally, whilst others allow a little more margin at the bottom than at the top. With a finely pointed pencil mark the mount lightly at the two opposite corners — for instance, the top right-hand corner and the bottom left-hand corner. Use the pencil very lightly, but just mark the position of the corner by making a line like an Ij round it, this will be a convenient guide hereafter to know where exactly to put the print down. Mounting Prints. 119 Place tlie print on the cutting-slab and put in the middle a small quantity of paste, or glue, and distribute it all over the back of the print with a roller squeege; then lift the print up and lay it on the mount and place over it a piece of waxed paper, or, better still, a piece of thin mackiotosh cloth, the rubber side being placed next the surface of the print, and then with a roller squeegee, rub the print w^ell into contact, lift up the cloth, and allow to dry. This method may be used for all prints except those which have a very high surface, such as the gelatino- chloride papers, and the best way to mount these is to procure from a dealer some special backing paper, which should be pasted and stuck dewn to the print w^hilst it is on the glass: the two should be allowed to dry together, and stripped together, aud then mounted. By using the waterproof backing paper, the paste or glue is prevented from penetrating through the paper and spoiling the high surface of the paper. The remarks made as to the choice of quiet and unobtrusive mounts applies v/ith equal force to the choice of frames. The quieter and neater the framing is the better; all such abominations as gilt or silver filngree frames with internal mounts of brillant coloured plashes should be avoided. For pictures which are genei'nlly dark in tone, it may be remembered that light mounts and licj;ht frames will apparently increase their depth of colour; whilst for very light pictures dark mounts and frames will throw them into greater prominence. This is a subject upon which much has been written, but the matter must be left to the individual taste of the w^orker. CHAPTER XXII I. Lantern Slides. Photograpliy has sometimes been stigmatised as somewhat a selfish hobby, because the results are as a rule confined to the opei'ator himself. With lautern slides, however, we can amuse not only those of our own household, but also larger audiences, and relieve the tedium, aad for a time make even the sick and jioor forget their misery and pain. If we work with a quarter-plate camera it is possible to make the lantern slides by contact, but if a larger plate than this is used we must either sacrifice a coDsiderable po tion of the subject or else copy the negative in the camera. Contact printing is of course much easier than working, or reducing as it is called, with the camera. The lantern slide used in England is of one regulation size 31/4 X 31/4 iuches, and plates specially prepared for lantern slide making can be obtained commercially. They are somewhat similar to bromide paper as regards treatment, and are equally as sensitive to light; although made also in character somewhat similar to alpha paper. To make a lantern slide by contact, place the negative, film up, in a printing frame, and over it place one of the Icintern plates, holding the frame up to the dark-room light and adjusting the lantern plate till just the right amount of subject is included; then put the back into position and expose to artificial light, either gas or lamplight, for from ten to thirty seconds at a dis- tance of eighteen to twenty-four inches. The same plan may Lauic7'n Slides. 12 1 be adopted for finding the exposure with lantern plates as was suggested for bromide paper. The plate is then ready for develop- ment, and this may be etfected by one of the developers suggest- d for bromide paper, or one of the following. By altering the duration of exposure and the developer, various tones may be obtained, ranging from a Warm brown to a pure black. As a rule the warm brown tones are more pleasing and show up better on the screen; and manufacturers recognising this have placed special makes of plates on the market to give warm tones. Pyro Developer. No. 1. Pyrogallic acid * 40 grs. Potassium metabisulphite 120 „ Distilled water to make 20 ozs. No. 2. Liquor ammonia 21/2 drachms. Ammonium bromide 40 grs. Distilled water to make 20 ozs. Mix in equal parts just before use. This gives warm brown to brownish black tones. Pyro-soda Developer. "Washing soda 2 ozs. Ammonium bromide 20 grs. Distilled water to make 16 ozs. Just before use add to every ounce of the above 2 grains of dry pyro. This developer cannot be used more thau once, but it gives very rich warm purple tones. After development the slide should be rinsed with water and then tixed in the acid fixing bath. The development of a lantern plate presents no particular difficulties beyond learning exactly how far to develop, and what should be the character of the finished slide. As a rule it may be considered esseutial that the highest lights of the picture 122 A B C of Photography . should be clear glass and should not be stained or discoloured, and yet at the same time the deepest shadows must not be so blocked as to make the result look heavy. It is advisable always to treat lantern slides after well wash- ing, after fixing, to a clearing bath composed of for ten minutes and then well wash and allow to dry. Gelatino-chloride plates or chlorobromide lantern plates should always be developed with ferrous oxalate or hydroquinone, and as they are somewhat slow it will be found convenient to use magnesium ribbon as the source of light. Magnesium ribbon may be obtained commercially at a very cheap rate, and when ignited gives a dazzling white flame. The quantity required will vary with the density of the negative and the colour of the slide that is desired, and may vary from two up to six inches. There is only one point to be careful of in using this and that is not to burn the fingers. The required quantity should be cut off and held between a pair of pliers, or even slipped between the blades of a pair of scissors. A match held underneath the free end will readily light it, and the burning ribbon should be held at about three feet from the printing frame containing the negative and lantern plate. With all commercial lantern plates fairly full instructions will be found, and these may be followed, or modified by using one of the developers here recommended. There is only one piece of advice I would give beginners, and that is, having once chosen a brand of plate, stick to it till a good slide can be turned out. By chopping and changing about, first from one make to another, good results are far less likely to be obtained than strict adherence to one brand. Lantern slide making by reduction is considerably more trouble, requires a longer time and there is considerably greater risk of failure. It may be performed by daylight, or artificial light, and of the two the latter is far preferable, as it is more Citric acid. . . Chrome alum AVater 1/2 oz. V2 . 20 ozs. Lantern Slides. 123 constant and enables us to work at nigLt and in the winter quite independently of daylight. Elaborate cameras are con- structed specially for lantern slide making, but a simple home- made apparatus will serve equally as well. Procure a wooden box, an empty soap box will do, and remove the lid. In the bottom cut out an aperture big enough just to hold the negative in position. An inner frame- work, nailed inside the box and projecting about an eighth of an inch over the negative, will prevent it from falling down inside, whilst two small brass catches on either side on the outside will keep it from falling down on that side. This can be placed on a table, or against the window if daylight is to be used. Mark out on the ceutre (jf the ground glass of the camera a 31/4 X 31/4 in. square, with lead pencil. Now set up the camera on the stand in the ordinary way ; if the negative is against a window, or if the negative has been placed on the table the camera may be placed on the table or a pile of books, aud a heavy book placed on top of it resting on the front and the back to keep it steady. The negative should now be sharply focussed on the ground glass and the image made to fall as centrally as possible on the 31/4 in. square. It will be found rather difficult at first to focus the image, but the proper distance to place the camera from the negative may be found by a very simple calculation. Divide the longer base of the negative by the longer base of the lantern plate, to the quotient add 1 and multiply by the focus of the lens, the result will be the distance that should be between the leos and negative. We will take an example: we want to make a lantern slide from a half plate ne,2:ative 6 1/2 X 43/4 ; obviously the longer base of this is 6V2» then as the lantern plate is square we divide 6^/2 by 31/4 ; thus, 6V2 -f 31/4 1= 2 to this we add 1 2 + 1 = 3 and multiply by the focus of the lens, which we will assume to be 8 ins., then 3 X 8 zz 24 ins A B C of Photography : this then will be the correct distance between the lens and negative. To find the distance between the lens and lantern plate, the distance found by the last method is divided by the first quotient we obtained, which was 2, then 24 2 = 12 whi^h is the correct distance from the lens to lantern plate. Having placed the camera at the proper distance and racked the camera out, cover ths space between the lens and negative with the focussing cloth so as to keep out the light. When daylight is used the exposure may vary from twenty to sixty seconds, or even more. The most convenient artificial light is certainiy magnesium ribbon, and I should always recommend the use of it. Behind the negative, about an inch from it, should be placed a sheet of ground glass, and behind this should be burnt the ribbon. The length may vary from eighteen to sixty inches according to the density of the negative and the rapidity of the lantern plate ; but during the whole time of exposure the ribbon must not be kept in one place, but kept constantly m.oving about all over the ground glass so as to equalise the lighting of the negative. The treatment of lantern slides exposed in this way is precisely the same as those made by contact printing, and therefore no special comment is required. When the lantern slide is finished it only requires masking and binding to be refidy for use. Masks are pieces of black paper with particular shaped ojjenings cut in them, and may be obtained commercially at a very reasonable rate. Binding strips are long strips of gummed paper which are used to fasten round the edges to keep the slide from being broken andf also to keep it in contact with its cover glass, which is merely a piece of plain glass the same size as the slide. The particular shaped mask which is most suited to the comxposition of the picture, should be laid on the film of the lantern slide, and over the mask one of the cover glasse3 carefully cleaned. A binding strip should now^ belaid flat on the table, and one end of it, for about 3 l/g inches, damped either with Lantern Slides. 125 a wet sponge or a brush charged with paste. The binding strips are sent out ready gummed, but too often the gum refuses to stick well, this is why the paste is suggested. The lantern slide and its mask and cover glass should now be lifted up and one edge pressed firmly down on to the wet binding strip, and the edge of the latter smoothed down on to the glass with the aid of a handkerchief or a clean duster, the pressure being maintained till it adheres ; the slide should now be carefully laid on one side for at least ten minutes. It will be found a good plan to wait till about half a dozen or more slides are ready for binding, and then do them one after the other as sugtrested above. By the time the last of a lot has been thus treated, the first may be taken up, another 31/4 inches of the binding strip wetted and stuck down, and this repeated in turn for each slide and for each side till th^y are all bound up. By working with this method there will be no danger of the slide and cover glass slipping, and a much neater job can be made of it. The only thing left to do now is to mark the slides, or spot them, as it is called. The 'spotting' tells the lantern operator the exact position in which the slides should be placed in the lantern to show correctly on the screen. To determine where the marks or spots, which are usually small circles of white paper, should be placed, hold the slide against a sheet of white paper so that the subject appears as it should on the screen and as it was seen in nature, then the proper place for the spots is at the top of the slide next the eye. When the slide is placed in the lantern these spots are placed downwards next the condenser, that is, the slide is placed upside down, and then the view will appear right* on the screen. CHAPTER XXIV. Enlarging". If the beginner commences the practice of pkotography with a small camera, there will be a great longing as progress is made to turn out big pictures, and in many cases I have known operators to sell their small cameras and purchase larger ones. This is a procedure which t cannot commend. I have already stated that small cameras are more convenient to carry about, and by enlarging we can obtain, from the small negatives, prints up to at least 12X10 inches, or even larger. We can use either daylight or artificial light for enlarging, and whilst daylight is convenient as requiring very little apparatus, artificial light enables us to work with more certainty of results, to work at night too, when other photographic work cannot be done. The apparatus required for daylight enlarging is not very ex- pensive, but it entails a larger apparatus, or the devotion of the dark room to this work only, for the time being. In the shutter of the dark-room window should be cut an aperture large enough to take the negative to be enlarged. The ordinary camera may be used instead of one specially constructed for the purpose, particularly if it is of the front focussing pat- tern. The negative, instead of being placed in a frame in the window, may be placed in the ordinary dark slide with the usual dividing piece removed and both shutters withdrawn, and then this inserted in the usual grooves of the camera. The camera may, if necessary, be supported on a box or other convenient support as shown in the sketch, with the lens pointing in. A Enlarging. 127 fairly long board or bench, on which may be supported the board to receive the bromide paper, will also be found necessary. The negative being placed in position, with the camera close up to it, the light passing through the negative is taken up by the lens, and an enlarg«-d image of the negative projected upon any surface placed opposite it. There are with enlarging as with lantern-slide mukiug, fixed distances for the negative lens and sensitive surfaces, and these are found by the same rules as for slide making. We will assume that we wish to enlarge from quarter plate to 12 X 10 inches. Then dividing the longer base of the desired enlargement by the longer base of the negative w^e find the ratio of image to object; 48 13 ^ 41/4 - then 17^ ^ 17' which multiplied by the focus of lens, which we will assume to be 5 inches, will give us the distance between lens and sensi- tive paper, 17 X5 = 191/8 inches. and dividing this distance by the ratio Fig. 14. 128 A B C of Photography . of image to object, we have the distance between lens and negative, viz., 191/8 -^gz=:63/4 inches. It is important that the negative should be evenly illumin- ated, acd unless a perfectly uninterrupted view of the sky can be obtained through the aperture iu the shutter, a white reflector should be placed outside at an angle of 45° as shown ia the sketch. This reflector may be either wood, painted white, or else a piece of white card. To carry the sensitive paper, an ordinary drawing board may be used, or preferably a large printii g frame of the required size. The printing frame may be obtained already provided with a sheet of plate glass which will keep the paper flat during ex- posure. To fucus the image sharply, a piece of ground glass should be placed in the frame with its ground surface next the plate glass. This is a convenient arrangement, as the operator can stand behind the frame and focus sharply by racking the lens in or out. The focus should be adjusted for a point mid- way between the centre and margin of the picture, and then if not sharp all over, the stops may be inserted, in turn, till sharp definition is obtained. As a rule it will be found that F/16 will be quite small enough to ensure sharpness all over. When the drawing board is used, a piece of white paper should be pinned on to it and the focus obtained first on this. When the whole image is sharp, the ground glass or white paper may be replaced by the sensitive bromide paper and the exposure made. The convenience of the printing frame will now be seen, as the back of the frame will press the paper into contact with the plate glass and keep it perfectly flat. Whilst putting the bromiile paper into position the lens must be capped, and only the ordinary red light of the dark room usecl. There is one important point, and that is to see that the image on the sensitive paper appears as it did in nature, and is not reversed. To ensure this the negative should be placed upside down and with the film side away from the lens. To estimate the exposure for enlarging is always a difficult Enlarging, matter and it will be fouDd safer to expose a small piece of bromide paper, of quarter-plate size, in one portion of tbe picture which contains a fair amount of half tone as w^ll as some high lights and shadows. It is almost impossible to give any satisfactory guide, but with a negative of ordinary character in the middle of the day in June, with a lens working atF/16 the exposure may vary from 40 to- 90 seconds. For artificial light the most convenient source of light is the ordinary incandescent or Welsbach burner, or else magnesium ribbon. The actual light from the Welsbach burners should not be used, but the reflection from a white surface. Any large box, such as an empty cube-sugar box, may be employed, if in the bottom of it, an aperture is cut large enough to take the negative. The lights should be placed one on either side of this aperture, and then opposite it a sheet of white cardboard which will reflect the light through the negative. The camera and bromide paper may be used in exactly the same way as for daylight, as shown in the accompanying sketch, but care must be taken to exclude all light except that coming through the lens from the paper, which may be done by covering over the space between lens and paper with an opaque cloth. If magnesium ribbon is used, a piece of ground glass should be placed about an inch from the negative to diff'use the light, and the ribbon moved about during the whole time of exposure so as to even the light. To estimate the exposure the small piece of bromide paper should be exposed exactly as described above for daylight. The development and after-treatment of enlargements is pre- cisely the same as that for ordinary bromide paper exposed by contact. For portraits, especially, and also for nearly all enlarging, a rough surface paper will be found to give, as a rule, the best results. It may be considered desirable for portraits, especially for head and shoulders only, to vignette the enlargements, that is to shade off the edges. This can be very easily done by procuring a piece of card of fair size, and cutting in it a small hole of the shape desired for the vignette, but not much larger 130 A B C of Photo gi'Liphy , than the full size of the lens, and this, held between the lens and the bromide paper and moved backwards and forwards during exposure, will give a nice soft vignette. The nearer the lens the cardboard is held the larger the vignette, whilst the nearer the sensitive paper the smaller the vignette, that is, the less subject will be shown on the paper. Instead of using gas we may use merely an oil lamp, such as the Defries, Beige or an ordinary duplex, when it should be ])laced in a cube-sugar b->x, with a -piece of ground glass near the lamp, a hole being cut in the side of the box to receive the negative, the ordinary camera and lens being used outside, to project the enlarged image on to the sensitive paper. "When larger pieces of paper are used it will of course be necessary to have dishes corresponding in size, and for those who wish to make their own the following notes may be useful. A special prepared waterproof paper can be obtained com- mercially, and it should be purchased cut" to size which must be at least four inches, and six inches is preferable, larger each way than the sheet of bromide paper. It should be folded on each side, the folds being two or three inches; the corners niay ihen be pinched together and the sides made to stand up so as to form a dish, whilst the corners may be pinched together with w^ooden American clips. These dishes are convenient even in small sizes for travelling, but when the larger sizes are used they require a piece of flat wood pla€ed underneath them to enable them to be lifted, and whilst they may serve as makeshifts they are not to be commended for serious work. Wooden trays are" far more convenient; and many a box-lid can be rendered perfectly watertight wath a little trouble. It is needless to remark that lids should be chosen without large cracks; any corner cracks may be filled with putty, and alter this is dry, the whole dish may be made watertight by giving it a coating of the followiny,' solution: v Asphalt 2 ozs. Mineral naptha 5 ozs. Pure indiarubber 30 grs. Instead of using the pure rubber which is sometimes difficult \ Enlarging. to obtain, the rubber cement used by cyclUts to repair their tyres may be used instead of it Two coatings of this, which should b3 freely applied with a brush, each coat being allowed to thoroughly dry first, will render any wood or cardboard dish watertight, so that by its aid, the cardboard lids of plate boxes, or even the boxes themselves may be rendered watertight and serviceable dishes. There is only one precaution to be observed in using this solution and that is not to apply it near an open fire or light of any kind. The vapour is very inflammable, and serious ex- plosions may occur if this precaution is not observed. It is better to use it in the open air. CHAPTER XXV. Portraiture. Probably one of the first things tbe beginner will attempt wben he has obtained his camera, will be to take the portraits of his friends and relations. It seems so simple to take a portrait, and yet it is really one of the moot diflBcult of all branches of photography, unless one has a studio to work in. The lens usually employed may of course be used with ex- cellent results, provided that it works at a fairly large aperture, yS for instance; the landscape lens may be used, although this works only at but it means of course a much longer ex- posure. There are many new types of lenses on the market now which work at F/5-6, F/6, or thereabouts, which are not only very suitable for all-round work, bat also for portraiture. The lens specially designed for portraiture and called Hhe por- trait lens' is not an instrument I can recommend to beginners, it is extremely heavy and unwieldy, in fact far too heavy for many of the modern makes of cameras, and moreover it is very costly and is not suitable for all-round work. One of the cheapest and best lenses for portraiture is the ordinary spectacle lens. These can be boiight in sets, of various foci suitable for the size of plate used, at about one-fifth of the price required lor the same number of lenses of the ordinary make, but they have the disadvantage of not being achromatic, that is, when the image is sharply focussed on the ground glass, it will not be sharp on the plate. This, however, will not be Portraiture, 133 such a great drawback, as after focussing, the lens may he moved a little nearer to the plate, about one-fiftieth of its focus is the usual amount, and the image will then be found fairly sharp, not quite so, but this slight softness, or diSfusion, as it is termed, is decidedly pleasing in portraiture, as it softens wrinkles, freckles and other skin blemishes. To make a spectacle portrait lens is by no means a difficult matter. We can either use the brass mount of the ordinary lens or merely a piece of the ordinary cardboard postal tube. The brass mount will be found more convenient as it will, of course, be provided with the usual slot for diaphragms, etc. From an optician procure two or three circular spectacle lenses, the periscopic is the best form ; these should be chosen of the required focus, which for a quarter plate may be 6, 8 and 12 inches focus, and also of the ntcessary diameter so that they will fit into the tube. They may be bought with the edges nicely ground olf for about sixpence each. Now procure a piece of postal tube which will just slide easily into the lens tube Remove the ordinary lens, cut off a narrow strip of the postal tube, about a quarter or three-eighths of an inch, and slip this into the brass tube from the back. Now cut off another ring from the postal tube, about the same width or a little less, and cut this through at the join, when it will naturally spring apart a little bit. The spectacle lens should now be placed in the brass tube, close up to the first ring of cardboard, with the hollow side of the lens facing the front of the tube where the diaphragms usually are ; then slip in behind it the second card ring which has been cut through : no difficulty will be found in doing this if the cut ends be placed one over the other and not with the edges together, and the ring lightly nipped, when it will slip into the tube quite easily, and when let go will spring out and hold the lens firmly in position. The ordinary diaphragms may be used, but unless they are of fair size, temporary ones cut out of thin black cardboard should be made, and with apertures corresponding to one-sixth or one- seventh of the focus. Using the spectacle lens at such large apertures it will be found that comparatively short expos- 6 134 ABCof Photography. ures may be given with soft, almost drawing- like results wMch are very pleasing. For portraiture rapid plates should be used, the most rapid that can be obtained, because they enable ooe to give much shorter exposure which is always a consideration in portraiture, especially with old, nervous, and also very young sitters. It will also be found an advantage to use isochromatic plates as they do not show freckles quite so plainly. (See Chap. XXVIII.) Portraiture in an ordinary sitting-r^om is by no. means easy. In the first place, the windows are frequently small, ueatly draped with curtains, and probably provided with a blind, all of which help to subdue what little light struggles through or is Dot kept off by an opposite row of houses. In all cases the curtains should be looped back and the blind drawn up as high as possible; and the windo^r should be clean — dirty glass will stop out a very large percentage of the light. It will naturally be assumed that the best place for the sitter is as near the window as possible, but it will be found that if the sitter is sitting sideways to the window, one half of the face will be very brightly lit, whilst the other will be in deep shadow, and unless a very long exposure be given, the resulting negative will yield prints which look as though there was only one side to the face. The accompanying plan may be assumed to be that typical of mauy rooms 30 i @ C a Fig. 15. which are lit by two windows A, B. If the windows are near to one another, one should be blocked out entirely by drawing down Portraiture. 135 the blind and drawing the curtains ; if they are some distance apart, the second window may be ignored and left in statu quo. The best lighting will be obtained in a room of the above type by placing the sitter about S 'and the camera about H or C, according to whether a full face or profile only is required. For full-length portraits the camera will, of course, have to be placed -further off, according to the focus of the lees, about E. Behind the sitter at G we may place a background, which may be either a plain or coloured curtain. Blankets make very convenieut back- grounds, and may be supported on the domestic clothes-horse, or hung over a piece of cloihes-line, fastened to two convenient bits of furniture, if one is not allowed to drive nails into the wall. F represents a reflector; this is almost always essential to lighten up the shadow side of the face, and nothing is better than two rather large sheets of ordinary newspaper spread over some chairs or a clothes-horse, the light reflected from this is soft and diffused. Frequently a sitter may desire to be photographed doing some work, such as may happen to be his or her daily occupation or relaxation, then, if possible, by all means humour them, but be careful not to allow them to fall into so-called natural attitudes which, when reproduced by photography, are frequently ungraceful and inappropriate. It must not be forgotten that when using short focus lenses there is a tendency to exaggerate perspective, that is, near objects look much larger than those further off. This is important, or otherwise you may find that a lady's hand or foot, which is held at some little distance from the body, will appear larger in proportion to the rest of the body. Then again it is a curious fact, not known by many, that few people are alike on both sides of the face and that one side is better than the other for photography ; as a rule this will be found to be the left side Then again, the presence of disfiguring scars or moles should be looked for and avoided if possible. With sitters with very pi'ominent noses or long upper lips, far more pleasing results will be obtained by slightly raising the camera and looking down upon the face, though as a general 136 A B C of Photography . rule it may be considered advisable to place tbe camera on a level with the eyes of tbe sitter. One very common fault witb amateurs' portraiture is to see tbe bead directed to one point, wbilst tbe eyes are directed to quite anotber. Tbis gives an absurd appearance to the face and sbould be rarely permitted. To avoid it is not difficult, place a fair sized looking-glass so tbat tbe sitter can see bim or herself in it, and as a rule they v^^ill not only direct tbe eyes in tbe right direction, but also put on a more natural expression. Instead of using an artificial background, it will sometimes be found extremely convenient to use tbe ordinary surroundings of tbe room, and thus show a lady pouring out tea, or sitting by tbe windov^r working, or a gentleman sitting at bis desk writing. Tbe only point to be observed in such work is tbat it will be necessary to use smaller stops, so as to get more of tbe subject sharp. There is one little point witb regard to tbe composi- tion of tbe picture, and that is to avoid as far as possible very bright objects, such as small mirrors or w^bite china, these appear very distinct in tbe print and distract tbe eye from tbe figure which sbould be tbe principal object. If a greenhouse or conservatory is attached to the bouse, good portraits can be made in it, but, of course, one is somewhat limited to accessories, which must be tbe usual plants, etc., and it is almost necessary to employ a plain background, as the pattern of tbe window bars, sashes, etc., are extremely unpleasant. It is, however, far easier to obtain even and soft lighting in a greenhouse with far shorter exposures. Tbe only defect as a rule in such work is tbe excessively strong top lighting which- casts somewhat pronounced shadows under tbe eyebrows, nose and chin; a defect which is also noticeable witb most out-door portraiture. To obviate tbis we m.ay construct a bead screen. Procure from an oilsbop a cane about 9 feet long, or a child's hoop may be used, and also purchase some rather fine muslin, sufficient to entirely cover tbe hoop or tbe circle formed by bending tbe cane into a circular form and fastening tbe edges together. The muslin sbould be tightly stretched over tbe frame _ and sewn into position. Tbis head screen can be nailed to a Portraihire, 137 short length of wood, and the latter tied to a broomstick or any convenient piece of wood, and we have then a head screen which can be held or supported over the sitter's head duriog; exposure, and the excessive top light will be considerably diminished and the heavy shadows softened down. These shadows may also be lightened by placing newspapers on the floor to throw the light up. Out-door portraiture will not be found very difficult if atten- tion to the use of the head screen is paid, and also if care is exercised not to include very near the sitter some obtrusive plants or branches which may look in the print as though growing out of the sitter's head. Sunlight should never be used for portraiture, at least sunlight should not be allowed to fall on the sitter's face, as it generally causes a screwing up of the eyes in order to avoid the glare. When sunlight falls through the branches and leaves of a tree too, it gives rise to small circular patches of light which are apt to give a spotty character to the print, which is not pleasing-, CHAPTER XXVI. Architectural Work. In ptotograpliing architectural work we at least have one satisfaction that does not always exist with other branches of out-door photography, and that is the subjects will not wave about with the wind, nor will they get tired of being still and shift their position; and there are few subjects which lend themselves more readily to our work or which enable us to compile more interesting records of bygone ages. All over Eng- land are scattered stately cathedrals, and ruined abbeys, but many a humble country church is extremely rich in subjects of great interest from an antiquarian or archBeological standpoint, and from the records obtained by photography we can trace the development of the various styles of architecture up to the present time. 'Architectural photography is conveniently divided into two classes, exterior and interior. The former dealing with the out- side, the other with the inside of buildings ; and of the two, the latter is far more difficult. In architectural work we shall find it necessary to pay great attention to the levelling of the camera and to the careful ad- justment of the swing back. If the camera is not perfectly level, but slopes down one side or the other, the building in the finished print will be found to appear to be falling over to that side. Then again it will frequently be found necessary to raise the front of the camera, and also to tilt the camera, in Architectural Work. 139 order to include all the top of a lofty spire or tower ; in such a case it will be found that, as pointed out in Chapter V., the swing back must be used in order to obtain the lines of the image parallel with those of the building. This is an extremely im^portant matter which should not be overlooked. We shall frequently find that, although we get as far away from a building as possible, we cannot include the whole of it, and then will be found the advantage of having a wide angle lens. For interior architectural photography, it will be necessary to obtain three pieces of cork, the ordinary bungs of about two to three inch diameter will be quite large enough. Into these the points of the tripod should be stuck and it will not slip on the polished stone floor of churches, etc. This little device should never be omitted from the outfit for architectural work, and it will also be found a great convenience to have the lower part of the legs of the tiipod sliding so as to adjust them for uneven places, and easily raise or lower the point of view. The most rapid plates obtainable should always be used for interior work, because as a rule the light is so poor that under- exposure is always to be feared. There is also one precaution which must always be taken, and that is the plates must be 'backed'. Backing a plate is coating the glass with some opaque or dark-coloured pigment, which prevents an extremely annoying defect called 'halation' from making its appearance. This will be described at length in the chapter devoted to 'Defects'. The estimation of exposure for interior work is always a difficult matter, but by using Watkins's exposure meter, as previously sug- gested, considerable assistance will be gained. It will always be found preferable to choose a day without brilliant sunshine for interior work, as otherwise the high lights may be too bright, and the shadows too heavy. In arranging the subject on the ground glass, avoid, if possible, a perfect balance; an interior of a church will look far better if the sides are not equally distant from the centre of the picture, and therefore, the camera should be placed rather to one side than I40 AB C of Photography. in the centre of the church. Avoid also, if possible, the inclusion in the near foreground of a series of rows of chairs or pews, and this may be done to a great extent by raising the camera front. Of course, there are exceptions to this rule, such as in the case of richly carved oak pews or seats, when they may be included and form a prominent part of the picture, though even then it will be better to obtain a special negative of them. Exterior work presents no particular difficulties. In choosing a *day for work avoid very brilliant sunshine, or if this is not possible, so choose the time of day that some shadows are cast, as much of the beauty of architecture depends upon the presence of shadows w^hich throw into relief the more prominent parts of the sculptnre, ornaments etc. For the same reason a very dull day will be found unsuitable, because the lighting is too even. It must not be thought that it will always be necessary to include all the building on one plate; if a general view is required then by all means aim for this; but as much of the beauty of architecture is in detail, it will generally be found that merely one door, a window, a buttress or even one little ornament, will make an interesting picture. To know exactly the value of each particular style of architecture, its various forms and details, it will, of course, be necessary to study some guide books on the subjects, and the simplest and yet most complete for beginners are Parker's Introduction to Gothic Architecture" and his "Concise Glossary of Architecture"; the former being the more interesting as it gives a succinct account of the various styles of architecture to be met with, and the latter being a dictionary of architectural terms. These two works will form a convenient stepping-stone to the more advanced manuals on architecture. CHAPTEii XXVII. Copying. One of the greatest advantages of photography is in the accurate and faithful reproduction of ohjects of all kinds, and in no branch is this more apparent than in copying diagrams, engravings and printed matter. It is not a difficult subject, but still requires some careful treatment and attention to details. In the first place the subject to be copied must be very evenly lighted; there must be no shadovv^ on it and one side must not be more brilliantly lit than the other. It will frequently be found that more even lighting can be found out of doors than indoors, though with a little management, evenness of lighting can be obtained indoors, especially if the subject is placed exactly opposite a window and the camera in the window place itself. A copying stand will be found a great convenience, and although these can be bought at very reasonable rates, still a home-made one will be found equally efficient and cheaper. To make a copying stand, procure a plaiik of deal, teak, or mahogany, the two latter are preferable as being decidedly less liable to warp, and good half-inch stuff will stand a lot of knocking about ; if deal or pitch-pine is used, then it should be well seasoned and certainly not less than one inch thick, and well planed up. The length of the plank must, of course, depend to a great extent upon the focus of the lens, but for anything up to half plate from six to nine feet will be found quite long enough. 142 A B C of Photography . At one end of tMs plank screw a drawing-board eithei* tiusli with the end or a little way from the end, in the latter case T irons can be used as a support; in the forpier, of course, the board can be screwed direct on to the plan end. This will form a support for the subject. To support Che camera, a travelling carriage must be made. This can be constructed of half-iuch oak, teak or mahogany ; deal or pme should not be used for this, and it should be th^ exact size of the base board. In the centre shoulfl l><> bored a hole large enough to take the camera screw, and, if necessary, this hole should be gouged out underneath to allow of the screw going right home. This carriage will want supporting on feet, and to ascertain the height of these, it will be necessary to measure first the height of the centre of the drawing-board from the plank which forms the base ; then the carriage must be supported at such a height that the leus, when the camera is screwed on the carriage, just comes opposite the centre of the board. The feet of the carriage should be merely two pieces of well-planed wood screwed on underneath. On the base board should now be nailed two long strips of wood, also well planed, and they should be just far enough apart to enable the carriage to slide easily between, without any side shift. These may be half-inch thick and one-inch wide, and, of course, the same length as the base board. The object of these is to keep the camera parallel with the subject, which is always an important point, otherwise one side of the object will be out of focus, whilst the other is sharp. The whole arrangement is shown in Eig. 16, from which it will be seen that the carriage will run easily between the side guides, and if the camera is screwed on it straight, the sensi- tive plate will always be kept parallel with the subject. It will also be noted that the drawing-board is represented with a series of cross lines and squares on it, these are merely drawn with pencil and serve as guides to enable the subject to be pinned or fastened centrally on the board, Such a stand is a great convenience, but not an absolute necessity, as of course the subject may be fastened to any convenient support and the camera usfd on its ordinary stand. When the matter to be copied is bound up in Copying, 143 a book it will be found iuconvenient to remove it, and to get over this ditficulty a piece of glass the same size as the page of the book should be procured, the sharp edges ground off, and then this placed behind the page and the two clipped smoothly together by wooden clips or india- rabber bands passed right round them ; then if the book be laid flat on the table, with the glass and illustration standing up, a pile of books or plate boxes behind the glass will keep it upright. The plates for making neg- atives of all black and white line drawings, or matter which includes printing matter, sketches in which lines only are used, engravings etc., should be of the kind specially made for this work, and which are known as ' process' or photo mechan- cal plates, and are very slow and give great density or opacity with clear glass. As with every thing else, exposure is always difficult, but this will depend upon the aperture of the lens, the rapidity of the plate and the intensity of the light. Here again Watkins's meter will he found of assistance. To calculate out the necessary distances between subject and lens and lens and plate, the simple rules described in Chapter XXII. may be used, as of course the cing. There rig. 16. operation is merely redu- is one point which it is essential we should note. 144 A B C of Photography and tliat is when using tlie lens so near an object the working focal length is increased, and as we do not increase the aperture, the lens will be really working at a smaller ratio aperture, or slower than when taking distant objects. An example will possibly make this clear. We want to reduce the page of a hymn-book measuring 6 X 4I/2 so as to obtain a negative from which we can make a lantern slide to project at a Sunday school meeting, and as it will save time to reduce it at once to lantern size, we assume that the printed matter must not measure more than three inches. We are using a 5-inch lens. Thea 6, the longer base of printed matter, -f- 3 zz 2. 2-{-lX5z=15, the distance between lens and printed matter. 15 2 71/2 ills., the distance between lens and plate. Now, our diaphragms are calculated out for a focal length of 5 inches, what will be their value when the lens is working at 71/2 inches. Suppose we find it necessary to use the stop marked P/16 to obtain sharpness all over the screen, then we know that tbe actual diameter of this stop is ^/^g ths of an inch, and therefore 7V2 -7- ^/l6 — therefore our stop is reduced in ratio aperture to P/24, and the exposure will have to bo reckoned out for this aperture. In developing plates exposed on such subjects, there is one main point to be kept in view : we want to obtain the printed matter or black lines as clear and as free from deposit as pQssible, so that they may afterwards print as deep a black as possible; and further we want the white paper to be represented by as black or opaque a deposit as possible, so that it shall be quite white in the reproduction. These two conditions are not difficult to fulfil provided correct exposure be given; but for the begiuner I strongly recommend him to ignore the latter and pay attention only to the obtaining of clear glass, as the neces- sary opacity can easily be obtained by using intensifiers afterwards. The developers for this work niay be either pyro, hydroqui- none or glycine, and of the three, possibly for a beginner either of the two latter will be found the easier to use. Copying, f45 Black and White Pyro Developer. No. 1. Pyro 60 grs. rotash metabisulphite 60 „ Distilled water to 10 ozs. No. 2. Washing soda Vs oz. Distilled water to 10 ozs. Potassium bromide 20 gra. For use, mix in equal parts. Black and Wliite Hydroquiaone Developer. No. 1. Hydroquinone 80 grs. Potash metabisulphit'.' 120 „ J, bromide 10 „ Water to 20 ozs. No. 2. Caustic potash 200 grs. Water to 20 ozs. Por use, mix in equal parts. Black and White Glycine Developer. No. 1. Glycine 30 grs. Sodium sulphite 1/4 ^z. Water to , 5 ozs. No. 2. Potash carbonate V2 o^- Water to 5 ozs. Potash bromide 10 grs. For use, mix in equal parts. The expose! plate should be placed in the dish and the mixed developer flowed over it exactly as previously described, 146 A B C of Photography, and the image as soon as it makes its appearance, carefully watched, and development allowed to proceed as long as there is not the siighiest sign of any deposit on the lines which re- present the prii ted matter. The moment this appears the plaie should be well washed and then fixed, and when thoroughly fixed should be examined by daylight. If now ibe lines are not quite clear glass, Belitzski's reducer should be flowed over it once or twice and the negative well washed and freed from hypo as previously described. If it now requires intensification, either the mercury and am- monia, or Monckhoven's intensifier may be used. As the necessary instructions for copying pictures and coloured objects differ somewhat from the above procedure, we shall con- sider these in a separate chapter. CHAPTER XXVII 1. Orthochromatic or Isochroinatic Plates: their Appli- cations and Uses. If we paint on a card a cross in bright chrome-yellow water colour, so that the paper does not show through, and then sur- round this with a square or other figure of deep cobalt blue and photograph this on an ordinary plate, we shall .find that the yellow cross will in the resulting prints appear dark, whilst the dark blue will appear almost white. This is due to the fact that the ordinary plates are not sensitive to yellow, and therefore it photographs more like black. To remedy this, plates are orthochromatised or rendered sensitive to colours, these bring orange yellow and green, which are nearly all reproduced too dark by photography. I need not enter into the history of this, nor trouble about the particular process adopted to attain this end, merely con- tenting myself by stating that it was discovered in 1873, and the plate manufacturer adds to his emulsion before it is spread upon the glass an aniline or other coal-tar dye, in minute quantities, which has the property of rendering the silver salts more sensitive to the colours above named. Isochromatic, or as they are for brevity's sake called, iso plates, will be found of great advantage in certain work, particularly in photographing all coloured objects, such as paintings, flowers; and also in portraiture ; and further in ordinary landscape work, more particularly at certain seasons of the year, notably in the 148 A B C of Photo g7'aphy. autumn and spring, but the great difference can only be seen when a yellow screen is used. The yellow screen is either a piece of yellow glass or collo- dion stained yellow, inserted in or near the lens, and its sole action is to reduce the action of tie blue rays of light so as to give the yellows, greens, and oranges more time to act, for although the plates are sensitized for these colours, they are still abnormally sensitive to the blues and violets. Yellow screens made of glass can be bought commercially, but they can be made at home for very small cost and in various depths of colour, which will be found extremely convenient. They are usually made by dissolving an aniline or other coal-tar dye, in enamel collodion, and coating plate glass with the same. The enamel collodion may be made as follows: Pyroxyline 7 grs. Absolute alcohol 1/2 oz. Methylated ether I/2 „ allow to dissolve and add Naphthol yellow 41/2 grs. shake well and allow to stand for at least twenty-four hours. Small plate-glass squares, larger than the lens, should be ob- tained ; for instance, for a lens of two inches diameter, three- inch squares should be purchased. The plate glass must be the thinnest and whitest obtainable; it must be well scrubbed in hut water both sides, rinsed in distilled water, and then placed in a warm place free from dust to dry, when it will be ready for coating. Take of the above yellow collodion one drachm and add to it seven drachms of the same enamel collodion without any dye; see that it is properly mixed, and then coat one of the three- inch squares and allow to dry ; when quite dry place another square of uncoated plate glass in contact with the film and bind the two with a lantern slide binding strip. This screen will act very strongly and require an increase of exposure of at least eight times the normal, and will be useful for all subjects in which a lot of blue is contained. Or t ho chromatic or Is o chromatic Plates. 149 Half a draclim of the above yellow collodion diluted with seven and a half drachms of plain collodion will give a screen requiring about five times the exposure, and can be used for subjects with rather less blues than the above. Fifteen minims of the above yellow collodion diluted with plain collodion to an ounce will give a screen requiring about two and a half times the normal exposure, and will be useful for landscape work and photographing flowers. The best place for the screen is inside the camera, behind the lens, and it can easily be fastened to the back of the lens board by large headed drawing-pins, driven in quite close to the edge of the screen on all four sides. Tn this position it 13 less liable to damage and also will not cause diffused light to be spread over the camera, and is therefore not so likely to cause fog. In landscape work, when used with iso plates, the palest screen will always ensure the obtaining of any clouds which may be floating about at the time of exposure, which will usually add much to the artistic effect of the prints. By using the second tint screen, we can obtain at any time photographs of the beautiful cloud forms which float about, and to the study of which many photographers devote considerable time. Eor cloud work, only slow iso plates and the second tint screen with stop 17 16 should be used, and an exposure about one-tenth to one quarter of a second given. Flowers vv^ill, as photographic subjects, well repay the little trouble required to take them. Somewhat careless, but artistic arrangement is better than any stiflf-set pattern, and if cut flowers are employed, the vase containing them should be of a quiet and inoff'ensive pattern so as not to detract from the flowers themselves. The background too should be carefully chosen. Dark flowers should be thrown up by a pale grey or cream, whilst light flowers should be placed against a darker ground. In every case the background must be plain without any pattern and also without any creases or folds. Some of the so-called self-coloured papers, w^hich caa be bought at stationers very cheaply, make admirable backgrounds. The question as to the use of the yellow screen when photo- A B C of Photography, graphing flowe s, is always a difficult one to give any advice npon, because so much depends upon the colours of the flowers, but it may be taken as a very fair rule, that only when there are blue or violet flowers included^ will the palest screen be necessary. It is too often used when unnecessary, with the result that yellow flowers are reproduced as quite white, which of course is false. For fruit studies, precisely the same rules may be adopted as to the use of the screen and coloured background. The photographing of coloured materials, china, etc., call for no special comment. For the correct reproduction of paii>tings, whether oil or water-colour, chromolithography and illuminated missals etc., somewhat more instructions are required. In the first place, evenness of lighting is essential, or else shadows may be cast by the brush marks in the case of oil paintings, which, although they may be useful to artists, are not as a general rule considered desirable for general work. Practically the hints which have been given as to the illumination of black and white objects, apply also to these coloured objects. There is, however, one decided ad- vantage which will be met with in photographing paintings and other coloure I objrots, and thut is the possibility of working at night. As the iso plates are rendered sensitive to yellow, and most artificial light is yellow, it is possible not only to obtain excellent negatives of coloured objects by gas or lamplight, but the yellow screen may be almost entirely omitted, except in the case of very brilliant masses of blue, when the palest tint screen may be used. The best system of lighting for oil paintings and by arlificial light is to employ two lamps, one on either side of the lens, with reflectors behind them, as shown in Fig. 17. The reflectors may be either pieces of white cardboard bi'nt to shape, or else may be made of sheet tin by a plumber, and should then be painted white inside, wdth ordinary white paint or AspinalFs enamel. The exposure required for coloured objects is a difficult matter to guage. More difficult almost than any other branch of photographic work. In the case of flowers and fruit there is not Orthochromatic or Isochromatic Plates, i 5 r so mucli trouble, as in no case dofs it extend to more than a few seconds. But with paintings it is entirely different; the exposure may vary from a few minutes to hours, according to Fig. 17. the nature of the painting, the depth ot screen, and the nature of the light. Water-colours require the least, then chromo- iithos and modern oil paintings, painted in brilliant colours, and finally, the old masters and oil paintings, in which in many cases the pigments have turned to a general deep brown tone, when hours may be required. Still, a lew experiments will give considerable assistance, and more , can be learnt from half a dozen failures than any amount of writing. CHAPTER XXIX. Photography by Artificial and Flash Light. Magnesium, a silvery white metal whicli can be obtained in tbe form of a powder, wire, or ribbon, readily burns in air, and yields a light of very great brilliancy which enables us to take portraits, the interior of rooms and other objects in a very bj'ief space of time at night. The use of magnesiiim is accompanied by one disadvantage, and that is the product of combustion, which is magnesia, settles down everywhere as a fine white powder. We will first of all consider the use of- magnesium ribbon, the wire is useless. The sitter for a portrait may be posed or arranged in the ordinary way, the only precaution being that the background must not be too near, or else a heavy black shadow of the sitter will be thrown on to the same. It may perhaps be found somewhat difficult at first to focus the image sharply on the ground glass in consequence of the dim light, although as many gases or lamps should be kept burning ia the room as possible. If any difficulty is met with, light an ordinary candle and obtain the assistance of some one, or else make the sitter hold this candle on a level with the eyes, and then focus the flame sharply and be careful to see that the sitter does not now move. The magnesium ribbon can be obtained in almost any length at about two pence per yard, and the most rapid plates should be used. The quantity of ribbon required will vary considerably of course, this being dependent upon the aperture of the lens etc. The ribbon should be uncoiled and straightened as far as Photography by Artificial and Flash Light, 153 possible by being drawn througli the fingers over a pencil or the back of a knife, or similar object, and allowed to hang down through the hand, which should hold it about six inches from one end. On the top of a pair of steps placed just behind the camera, should be stood a lighted candle or small methylated spirit lamp, on a piece of board about a foot square. Having focussed, and having the candle or lamp readj^, tell the sitter to sit perfectly still, then mount the steps and light the ribbon at the lamp or candle flame, and as it burns away, feed it through the fingers with the other hand. Whilst the ribbon is burning keep it on the move over the board, which is useful to catch the burnt magnesium, for at least three-fourths of its lens;th, the final fourth should be transferred to the other hand and burnt on the opposite side of the camera. This is done to lighten up the shadow side of the face somewhat. There is one warning which should not be neglected — look out for your fingers, if the burning metal should happen to drop on them, the result will not be forgotten in a hurry. Preferable to ribbon is the use of magnesium powder, and this can be used by blowing it through a spirit flame. Properly constructed flash lamps may be obtained commercially at very reasonable rates ; but for those who wish to construct one for themselves, the following little dodge may be used. Procure three clay pipes with rather small bowls, and also one of the little cigarette holders made in the shape of a pipe. Break the clay pipes short off" at the bottom of the bowl, and stop up the hole with a little putty or plaster of Paris, the latter is better. Obtain a small wood or cardboard box just big enough to contain the bowls of the three pipes and the cigarette holder, the latter should have the stem left on, and this should pass through the bottom or side of the box, aud be arranged so that the edge of the bowl will be just an eighth of an inch above the edge of the box. Arrange round it as close as possible the pipe bowls, and in between, so as to entirely fill the box, pour liquid plaster of Paris and allow to set. Into the pipe bowls pack lightly either some ordinary wadding, tow or asbestos fibre. In the central* cigarette bowl place fifteen 154 A B C of Photography. ^jrains of magnesium powder. Now carefully pour a little methyl- ated spirit into the pipe bowjs, taking care not to allow any to damp the magnesium powder. To the free end of the cigarette holder protruding from the side of the box, attach about twelve inches of an indiarubber tube, such as is usually used for feeding bottles and which can be procured from auy chemist. ^ Now light the methylated spirit in the pipe bowls, and holding the head well away from the lamp, blow violently through the indiarubber tube, when the magnesium will be blown through the flames and burn with intense brilliancy. For tailing the interior of rooms or still objects, one such flash lamp will do, because it can be recharged and retired any number of times without fear of movement on the part of the inanimate objects. In the case of portraiture, however, one will not be sufficient, and three such lamps should be constructed. These lamps should be arranged as shown in the following diagram — in which S is the sitter, L L L the three lamps, C the camera, and R reflectors behind the lamps. ^ It will be found by no means \ easy to discharge three of these lamps at once by merely blowing through them, it will therefore be advisable to connect them by ordinary indiarubber gas tubing and small T pieces of brass or iron pipe, with a pair of oi bellows. The two lamps should J be about eighteen inches apart, *' and the nearest about eio:hteen inches from the camera; the Fig. 18. solitary lamp on the other side being also at this distance from the camera. The lamps should all be about six feet froru the ground, and should each be charged with about ten grains of magnesium. Ey using fifteen, twenty or thirteen grains of powder in each it will be possible to obtain successful results of a group of several people. Fhotography by Artificial and Flash Light. 155 Anotlier metliod of using plain magnesium powder is to pull out lightly a small tuft of pyroxylin or gun cotton, and place it on a biscuit-tin lid, a tea tray or any handy metal object, and to sprinkle over it about ten or fifteen grains of magnesium, then to fire the pile by means of a long taper. Mixtures of magnesium powder w ith various highly combustible, not to say explosive chemicals have been used for some time under the name of Hashing mixtures, and with care there is no danger in their use. Many formulae contnin poisonous chemicals, such as sulphide of antimony, and the fumes from this are danger- ous. The following, however, will be found quite harmless : Magnesium powder 96 grains. Potassium perchlorate (powder) . . . 140 ,, The potassium perchlorate should be bought powdered, and the proper quantity weighed out and spread on a sheet of white paper and then the magnesium added to it, and the two mixed with a long feather ; on no account must they be rubbed up together in a mortar or roughly used. The best way of firing this mixture is to use nitre paper, which can be made by soaking thick white blotting paper in a solution of saltpetre 1 oz., water 20 ozs., till thoroughly soaked, and then drying it. A piece of this paper should be rolled up fairly tightly into a spill, and then clipped in the cleft end of a piece of cane about twelve or eighteen inches long. The flash mixture, about fifteen or twenty grains of it, should be spread rather loosely on a tin ; the nitre paper ignited for a moment with a match and any flame blown out, when it will be seen to glow and smoulder, and with the smouldering end the flash mixture should be touched, when it will instantly burst into a brilliant flash of intense light. After having once fired any magnesium, a little time should be allowed for the white smoke to settle down, or otherwise the floating smoke will be illuminated by succeeding flashes and cause foggy plates. It is possible to obtain portraits by ordinary gas or lamp light if iso plates are used, but unless a goodly number of A B C of Photography . lights are burning, the exposure will be unduly prolonged. In any case it is advisable to allow the sitter to rest in as com- fortable a position as possible so as to avoid movement. The incandescent gas light will be found to require the least exposure, and fairly successful results can be obtained by using three of these burners. With a little trouble and care and one or two failures, successful results may be obtained of fireside groups. The sitters should bi arranged round the fire, and so that the actual fire is hidden from the lens. A piece of ordinary small gas-piping may be arranged so as to project within about six inches of the fire, which should be burning brightly, and in the gas piping should be placed a charge of magnesium or flash powder, and after having carefully focussed, the pow^der should be blown into the fire, when it will instantly burn; this process if successfully carried out, will represent the idea of a firelight chat in the gloaming. CHAPTER XXX. Pin-hole Photography. It was stated in Chapter III. that the lens was the most important part of the photographer's outfit, and whilst this is strictly true, yet at the same time it is the one piece of appa- ratus which &an be dispensed with ; for it is quite possible to take excellent photographs with a pin-hole instead of a lens. Although called a pin-hole, the minute aperture is usually made with a needle. Probably it will make the subject easier to understand if a little explanation is given first. An ordinary camera may be used, but instead of using a lens, a metal plale pierced with a very fine hole is used, through which the light reflected from the objects in front of the camera proceeds and forms, as with a lens an image upside down on the focussing screen or plate. This image is so faint that it cannot be seen on the ground glass in the ordinary way; but it is there, and will so affect the sensitive plate that on development a negative will be obtained which, if correctly exposed, will be a picture of the objects without the sharp definition of a lens, but of a soft diffused nature which is extremely pleasing for some classes of subjects. The focus of the pin-hole, or that distance at which the clearest definition will be obtained, depends upon its size. It will be somewhat difficult to drill very minute holes; for those who require them, Mr. Cox, of Parkstone, Dorset, can supply them. Thanks, however, to Mr. Watldns, for larger holes we can use needles, for he has measured the diameters of some needles made by Hall and Co. of Sudley and in the following table are given the commercial numbers of the needles and their diameters. A B C of Photography . No. of Needle Diameter. No. of Needle. D ameter. y V22 6 1/34 3 1/28 7 l/jc, 1/26 8 1/44 4 1/28 9 1/48 5 1/31 10 I54 To make the holes, some sheets of the very thinnest brass should be obtained, and about six of them placed one on top of the other and either screwed up tightly together in a vice or else heavily weighted so as to keep them close. The whole should be placed on several thicknesses of soft blottino; paper. The needle of the required diameter should now be chosen, held perpendicularly over the centre of the sheets of brass, and driven completely through by a series of gentle taps with a hammer. When the needle has passed right through, the middle leaves of brass should be examined, and if there is any burr or projec- tion round the edge of the hole, it should be smoothed off with a very fine file, and then the needle passed through again. The sheets of brass thus pierced may be cut by a pair of sharp scissors into the same shape and size as the Waterhouse diaphragm ; in the slot of the lens tube generally used for the ordinary diaphragms the pin-hole stop can be used; If the lens has the wheel or revolving diaphragm, the thin sheet brass may be cut iuto a circular shape and pressed up against the diaphragm plate by means of a small coil of wire, or split pieces of postal tube as described for spectacle lenses; care being taken that the pinhole is central and not to one side. It has already been stated that the focus of the pin-hole depended upon its size, the following table gives the focus for some of the various sized holes. Diameter of Hole. Eocus. Ratio Aperture. 1/250 i^ch 1 inch r/250 1/125 » 4 - 17500 Vso » 8 „ r/640 Veo » 16 „ F/960 1/50 » 24 „ r/1240 Pm-hole Photography. 159 Mr. Watkins gives the following table of foci, ratio aper- tures, and sizes of plates calculated out for use with his ex- posure meter, based on his table of needles (p. 150.) No. of Needle, Eatio Aperture. Focus. Size of Plate. 3 F/76 23 15 X 12 4 F/72 20 12X 10 5 I76O 15 10X8 6 1756 13 8V2X6I/.2 7 P/50 10 6I/0X43/4 8 1745 8 5X4 9 F/38 6 10 F/35 5 41/4X31/4 It will be noted that there is considerable discrepancy in the above tables, but this is due to the fact that they are calculated from two different mathematical tables, and actually there is a great divergence of opinion amongst mathematicians as to which is correct, and considerable latitude in focus is permissible with- out much difference being detected. It will also be noted that Mr. Watkins's gives comparatively large ratio apertures, this is done to avoid very large figures, so that in calculating out exposures with his meter for these pin-holes, the exposure will be in minutes and not seconds. To find the actual ratio aperture, supposing that one is not using the meter or one is not using exactly these distances, it is obvious that one has only to divide the extension of camera by the diameter of the hole to find the true ratio aperture in the ordinary way. In Mr. Watkins's table, also, it will be noted that he gives a certain sized plate for each focus; it is not of course necessary to use exactly this focus for the given sized plate, in this case the same law holds good as was stated with lenses, — the longer the focus the larger the image, — so that it may be convenient to have plates pierced with various sized apertures and use various extensions of camera in order to obtain enlarged images of objects from the same standpoint. CHAPTER XXX T. Stereoscopic Photography. Yenrs ago this branch of photography had a tremendous run, and there were very few houses that did not possess a stereo- scope and stock of stereograms, the term used to denote the priuts or slides viewed through the same. It is undoubtedly the most perfect of every branch of photography, giving as it does an appearance of relief and solidity to the objects which is extreme- ly realistic. It has for many years fallen into disuse, and only lately has there been a revival, and that entirely amongst amateurs ; whether it will ever become as fashionable as it previously was is open to question. It is possible to briefly explain the theory of stereoscopic vision., without entering very deeply into the mathematical part of the question. If we place a lighted candle at a distance of about three yards, then shut the left eye and hold at arm's length, with the right hand, a piece of card board, so that we can see the candle but not the flame, and then close the right eye and open the left: we shall find that we can not only see the candle flame, but that it will appear a long way from the edge of the card. And on repeating the experiment, but this time keeping both eyes open after the card has been adjusted, we shall find that we see totally diff'erent with each eye, and that what we see with two eyes is the sum of what each eye sees. So far we have considered entirely the production of pictures taken with one lens from one point of \iew, and therefore this Stereoscopic Photography. - 1 6 1 is quite on a par with using one eye only to see with. The results obtained with one lens or a monocular camera are flat and wauling in relief; they represent the objects iu nature as flat and without any roundness or solidity. If, however, we use two lenses separated by about the same distance as the eyes, and obtain two negatives side by side, and examine the prints from the same in a stereoscope, which is an instrument which enables us to combine the two pictures in one: we then obtain a perfect representation of the scene, taken with all the realistic solidity of nature and only wanting colour to make it perfect. Special cameras for stereoscopic works may be obtained of various sizes ; that which I most strongly recommend is the double- quarter plate which measures 6I/2 by 4I/4 inches. The only difference between a stereo camera and an ordinary one is that it is provided with a central partition antl two lenses. Any camera of half-plate size and over may be adapted for stereo- scopic work, by fitting to it a central partition and an extra lens front to carry two lenses side by side. The central partition should be made of black twill or velvet, the length of the same being equal to the greatest length to which the camera will extend; and to make it contract, narrow elastic should be sewn into the edges, whilst a hook at each end, top and bottom, which can be fastened to small eyes of stout wire driven into the front of the camera, and the back of the frame work of the same, will keep it in position. The lens board, as we have already stated, must have the two lenses separated by about the same distance as the eyes; this varies considerably with different people, and therefore as a general rule a fixed distance, which is three inches, is chosen from centre to centre. This is the best distance for ordinary work, though under special circumstances, less than this, even down to two and a quarter inches will be found enough. The lenses for stereoscopic work need not necessarily be rectili- nears, single len-es are quite good enough for all stereoscopic work, and five inches will be about the best focus; if another pair can be afforded, then 1 would recommend a pair of three-inch wide angles, and if another pair, a pair of 7-inch landscape lenses. A B C of Photography, The lenses must be very accurately paired, both as to focus and aperture, and this work is best doue by an optician. Tt will be found difficult to uncap and cap the lens simultan- eously if the caps are separate, they should therefore be fastened together by a narrow strip of wood, which may be glued to them as they rest on the lens tubes. It is, however, far preferable to obtain an instantaneous shutter specially constructed for stereo work. As regards the plates, there is nothing special to note, all makes can be obtained in the particular size for stereo work; or, of course, if a camera is adapted for stereo worky the ordinary plates will do. Focussing is effected in exactly the same way, only it must be remembered that there are two lenses now to stop down, and one must be careful not to neglect one in this respect. The exposure should for stereoscopic work be rather lull, that is inclining most decidedly to over-exposure, in order to avoid harshness in the resulting prints, which causes an extremely irritating defect, which will be treated of hereatter. Development, fixing and washing are the same as when only one lens is used, and call for no special comment except that it is advisable here also to avoid any tendency to harshness. It is possible to obtain stereoscopic negatives with one lens and one camera; we will first of all take the case of a half-plate camera, with square bellows, which has been provided with a central division. A lens front must be provided of extra length, this will of course depend upon the width of the camera front ; it must be of sufficient length to enable the lens to be shifted an inch and a half from the centre of the camera without un- covering any portion of the camera so as to admit light in through the front, this will probably require about three inches extra. On the camera front, mark accurately, on each side of the centre, a distance of one and a half inches, and mark accurately the centre of the lens board. Screw the lens flan^ie on to the lens board so that it is ju^t over the centre. The dark slides are filled with plates in the ordinary way, and after focussing Stereoscopic Photography, 163 the view on one side of the focussing screen and seeing that everything is sharp, insert the dark slide in the camera in the ordinary way, and draw the slide. Now see that the lens is opposite one of the marks on the camera front and uncap the lens, giving the exposure considered correct. Then cap the lens and shift the lens over to the side of the camera front to the other mark, and then give exactly the same exposure to the second half of the plate. When only a quarter-plate camera is to be used for stereo- scopic work, we must have recourse to another dodge, which consists in using a special top, shown in the following diagram, which can be used on the ordinary tripod top. It should be constructed of half-inch wood and of sufficient Jength to allow the camera to be shifted three inches. A hole {d) should be made to fasten it to the ordinary cam- ra top ; and a slot ij) I) made, to which to fasten the camera by means of a second screw, and in which it can be shifted from side to side. The disadvantage of these two methods of taking stereoscopic views is that it is not possible to take instantaneous views, and it may happen that the objects may move during the time necessary to make one exposure and shift the camera ; and farther, there is enormous difficulty in giving identical exposures to the two halves of the plate. When the stereoscopic negative has been obtained it is printed from in the ordinary way, either on bromide paper, platinotype or gelatino- or collodio- Fig. 19 chloride paper. The two latter are to be preferred ; but whatever be the printing process adopted there is still the one main thing to be observed, and that is not to obtain hard or brilliant prints. Prints which, when viewed by themselves in the ordinary way, look flat, overprinted and heavy, will, when combined in the stereoscope, look perfectly bright and natural. Whereas bright brilliant prints, when viewed through the stereo- scope, will look as though the whole view had been powdered A B C of Photography , with snow, an effect whicli is uttierly absurd when, forinstance, a summer landscape has been taken. On priming from the negative it will be seen that the two views are presented side by side, but that which was taken by the right-hand lens is on the left hand. It is essential, however, it the objects are to look natural, that the picture taken by the right-hand lens should be seen by the right-hand eye, and there fore they have to be cut in two and transposed. To explain this we must have recourse to one or two diagrams. Supposing, for instance, that we wish to take a stereoscopic picture of a card divided down the centre and bearing the words and letters, as shown in Fig. A. (See next page). It will be seen when the negative is held up as it was in the camera, that the result is as in B, and the print from this, when held the right way up, will present the appearance shown in C. From this it is obvious that as the square marked right should be seen by the right-hand eye, it will be necessary to 'cut the print in two at the dividing line and transpose them. There is, however, considerable danger, if care is not taken, that the two halves will become mixed up. To avoid this, lay the print face down- wards on the table, with the top of the picture away from you, and across the centre dividing line mark faintly with pencil a straight line, as shown in D. When the print is trimmed and cut, the two halves must now be turned, so that, when right way up, the pencil lines come at the side, as shown in E, and the prints will then be correctly placed. To trim the prints, cut them first down the centre through the dividing line, and now note some prominent object in the foreground of each picture, such as a stone, and trim the base of them by this, so that both are exactly level; now trim the right-hand print so that one quarter of an inch more sub- ject shows on the left of it than on the left of the left-hand print, and trim the left-hand print so that one quarter of an inch more subject shows on the right-hand side of it than shows on the right of the right-hand print. The total width of each print should be 2^/4 inches. This seems at first sight rather confusiug, but there can be no mistake about it, and to make Stereoscopic Photography, 165 6. z > / 2 5 6 1 ' ce/e V 5 4 7 8 z / 9 9 A B 5 6 / 2 7 8 4 D E 7 66 A B C of Photography, quite sure tliat tlie directions are understood, I will repeat them with a diagram. Each print is to be two and three-quarter inches in width. The right-hand print must show a quarter of an inch more subject on the left hand than the left print ; the left-hand print must show on& quarter of an inch more subject on the right than the right print. In Fig. 20 let A repre- sent the right-hand print and B the left-hand print, in each there are two prominent objects in the foreground, represented by the dotted lines marked respectively 1, 2, 3, 4, then there must be just one quarter of an inch more of the subject shown in A ,.5 ^, - \ I.. --.„T»^, -..I..-., ' Fig. 20. beyond 1 than is shown in B beyond 3; and in B there must be just one quarter of an inch more subject shown beyond 4 than is shown in A beyond 2. In mounting stereograms, dark chocolate, black or green mounts should be used, and the view, when seen in the stereoscope, will then appear as though framed in a dark frame. The two prints should be mounted with a quarter of an inch between them. Beautiful though the results are when paper stereograms are view^ed in the stereoscope, they cannot in any way equal the per- fection of relief and realism attained with transparencies. These are, unfortunately, not so easy to make, though if a little care is taken and system adopted, the results are not hard to obtain. In the first place, they may be made by copying in the camera, using the twin lenses and camera used to make the negative. We want also a support for the negative, and this can be made Stereoscopic Photography. 167 out of any wooden box of convenient size, wliicli can Le attached to a base board, or even placed upon the table. The box should take the form shown in Fig. 2i, the partition shown being Fig. 21. exactly in the centre, so that it divides the negative just at the line of separation of the two pictures. The ordinary stereo camera can be used, but the lens front must be made so that the distances between the centres of the negative are slightly wider apart than the centres of the trans- parencies. The box must of course have an aperture cut in it to take the negative, and the whole apparatus may be directed to the sky, or a white reflector used behind it, either for day or arti- ficial light, as describe! when treating of lantern slides. The negative is placed in its aperture upside down and with its film side away from the lenses, that is, it must be copied throagh its glass, the view will then appear the right way up on the focussing screen and exactly as it will appear in the stereoscope. To judge of the effect it will be advisable to temporarily affix to the focussing screen of the camera a mask, which can be bought commercially in various shapes, that most suitable to the composition of the picture being chosen ; and then to examine by the aid of a stereoscope the view as it appears on 1 68 A B C of Photography. the ground glass, for by this means one can easilj^ judge, although it will be a negative picture, of the final result of the trans- parency when viewed in the stereoscope. Precisely the same directions which have been given for prints, r.s to more subject being included on one side than the other etc., must be observed in making the transparency ; and precisely the same precautions to avoid hardness must be taken as in the case of prints. With this exception the making of the trans- parency is precisely the same as making kmtern slides by re- duction, though stereo transparencies must be more fully exposed and development pushed much further than with lantern slides. There is another method of making transparencies — by con- tact printing, which of course requires no camera, merely a special printing frame (which may be obtained from W. J. Chad- wick, 2, St. Mary Street, Manchester), which renders the making of transparencies very easy, and I give his description of the method of using it from his "Stereoscopic Manual." "The figures F, G, H represent a frame for printing transparencies the full size of the negatives. The front of the frame (Fig. F) is of solid w^ood, with an aperture in the centre, through which the printing is done. The frame should be 101/3 inches long inside, the aperture two inches and seven-eighths wnde, and exactly in the middle. "In Fig. G, the negative shown by diagonal lines has been placed in the frame, film side up, and adjusted with its left side over the aperture. The sensitive transparency plate is shown by horizontal lines, adjusted with its right end over the negative and the aperture in the frame. The back is now placed in position, held by the spring and two holders. After exposure the relative position of negative and plate must be changed, as shown at Fig. H, where the right end of the negative and the left end of the transparency plate are now^ over the aperture, and ready for the second printing. "The adjustment of the negative over the aperture will now be explained. It has been previously said that the beauty of a stereoscopic slide is greatly enhanced by producing the effect in I JO A B C of Photography mounting of seeing the picture through an ajierture or behind the mount, and this being the most effective style, we confine our remarks to it; namely, simply to print the pictures at two and seven-eighths centres, and to insert a paper mask similar to those used for lantern slides (only a double one), between the transparency and the cover glass, the centre of the mask being about one-eighth of an inch less than the centres of the pictures. '•When adjusting the negative for the first printing, as in Fig. G, observe some particular object, say the edge of a stone, or something of the kind in the foreground, that is cut hy the left edge of the aperture, and by a piece of cardboard to serve for a guide, th.e plate is applied in such a position that the centre of it is cut by the left edge of the aperture; the back of the frame is now applied and printing performed. We now remove the sensitive plate, refresh our memory with the 'stone in the foreground,' and slide the negative to the position, as in Pig. H, adjusting the particular 'stone in the foreground' as for the previous printing ; apply the plate by use of the guide, which is now turned to the other end, and if made correctly, it will produce the two pictures side by side with a clean cut line between them, without any space or overlapping. (If, how^- ever, there is a space left between the two pictures, the guide is not the right length for the plate, or the aperture is not in the centre of the frame.) "So far w^e have considered the printing of a transparency from a negative of the same size. We will now consider, making the standard size transparencies (61/4X81/4) from larger negatives. Of course in this case the printing frames must be made correspondingly larger, and provided with suitable guides, enabling various portions of the negative (via more or less fore- ground) to be printed from. "The illustrations G and H show such a frame for 6I/2 X 4V4 negatives. In Fig. G, the negative represented by diagonal lines, has been placed in the frame first, with the left-hand side over the aperture for printing: on the top of the negative the guide is placed, indicated by the white portion, and this is pushed close against the right-hand end of the frame. The transparency Stereoscopic Photography . 171 plate, indicated by the horizontal lines, is next placed in position, with its right end over the left end of the negative, and is pushed close against the gaide as shown; the back of the frame is now applied and printing proceeded with. "After the first printing, the plate and guide must be removed, the negative again adjusted, as already described; the guide is turned over and placed at the other end with the plate as shown in Fig. H. It is now ready for the second printing. "It will be seen that the guides not only fix definitely the position of the plate endways, but the tongue at the bottom, on which the sensitive plate rests, brings the plate to the centre of the negative, and preserves a true base line. With a series of these guides, having tongues of various widths, almost any portion of the negative can be printed, from ; thus more or less foreground, sky etc., can be included." It only remains now to detail the method of mounting stereo transparencies. Those which have been copied in the camera merely require a piece of ground glass and masking and binding to be finished, as the glass of the transparency is placed nest the eye. A suitably shaped mask should be adjusted to the transparency, then over this a sheet of the very finest ground glass placed, and the whole bound up together with binding strips. Ground glass is used to diff'use the light and prevent objects being seen through the transparency when examined in the stereo- scope. When contact printing is resorted to, the film of the trans- parency must be next the observer, therefore to preserve it from injury, it must have a plain cover glass placed over it after the mask has been adjusted, ar.d behind it a piece of ground glass, and then the whole bound up together. The ground glass is not absolutely necessary, but it is an improvement; still it may be dispensed with by using special transparency plates in which the film is coated on ground glass. There are several points in connection with the choice of sub- ject in stereoscopic work which should not be omitted. Although practically the ordinary rules of composition of the picture apply, 172 A B C of Photography. it must not be forgotten that tlie beauty of a stereogram is its relief, and therefore everything which will asaist in heightening the effect should be looked for and taken advantage of. A big stone or rock, the branch of a tree or bush, even railings should be utilized as foreground objects,, for by including these in the picture, the more distant planes are thrown back sjnd the effect of relief is much enhanced. One should always try and obtain some prominent object wdtliin five or six yards of the camera, and never a(tent]i)t to take long stretches, or panoramic view^s, they always look fiat and uninteresting. Little b'ts, such as an old gnarled oak, a corner of a hedgerow with perhaps a peep through it to the field beyond, an opea gate leading to a house, or a garden with steps and statuary, — and figures are extremely effective subjects for stereoscopic work: all these require sharp definition, not softness and out of focus results; for in nature, unless our eyesight is wrong, we do not see near things all fuzzy and without form. C H A P T E R X X X 1 1. Hand or Detective Cameras. Within tte last seven or eight years we have seen the growth of what are now called detective or hand cameras, which are so constructed that they may he carried in the hand and used without any stand or support, being merely steadied against the body or any convenient support. The commercial patterns differ considerably both in price and construction, some costing only a few shillings, whilst others cost as many pounds ; some being simple and easy to understand and work, whilst others require almost a handbook to their various movements and at least a month's work to enable one to use them. A hand camera really consists of the same essential parts as an ordinary camera — that is, a lens, a light-tight chamber or camera proper, and dark slides or some other device for holding the sensitive plates before and after exposure, so that they may not be affected by light otherwise than through the lens, and also a shutter. The usual size of hand cameras is the quarter plate, and this is the size I should strongly recommend. If smaller than this the pictures are too small, and if larger the camera must be bulky * and much increased in weight, and other difficulties are met with in practical work. The first question to be decided when purchasing a hand camera will necessarily be the amount which can be paid for 174 A B C of Photography. it upon this point I cannot, of course, give any assistance, and upon the price paid will depend to a great extent the perfection of the make, the multiplicity of the convenient move- ments, the quality of the lens, etc. The next question is whether the camera is to be fitted with dark slides or a magazine, and whether for plates or films The latter are, of course, a great convenience when on a journey on account of their light weight, the absence of any chance of breakage and the small compass into which they will pack. Films may also be obtained in long continuous rolJs, which when used in a special dark slide, enable one to reel off one hundred or less exposures without having recourse to a dark room, which is a great advantage when travelling on tour in Eoijland or the continent. The question of magazine or dark slides depends to a great extent upon personal taste. As a rule magazine cameras are only suitable for hand work, they cannot be used on a stand, or at least any view cannot be focusscd on a ground glass. Personally, I have a great preference for hand cameras which can be used on a stand and a view focussed in the ordinary way, as well as in the hand. This enables one to cope with a far greater range of subjects than those which are designed for handwork only. Dark slides are convenient because they enable one to use any make or rapidity of plate which one may think suitable to the particular subject, whereas with magazines, in the majority of cases at least one has to use the plates in rotation. On the other hand, for really quick work, where scenes are required to be taken very quickly one after the other, the time involved in withdrawing the shutter, inserting it after exposure, and turning the dark slide, may be valuable time lost, and totally ruin the chance of obtaining what we want. Magazines, on the other hand, are frequently constructed with such delicate movements that they are exceedingly liable to go wTong, and it is an open question whether it is worse to lose a picture by loss of time in changing the dark slide, or have the changing mechanism of the magazine go wrong at the critical Hand or Detective Cameras, 175 moment with the further chance of its sticking wrong for the rest of the day. I wdll now proceed to consider the various parts of the camera for hand or detective work. With regard to the lens, it need not necessarily be a recti- linear, though of course it is an advantage to have one because they work at larger apertures and thus enable one to give shorter exposures, or, in other words, to take objects moving more quickly. Single lenses can be used provided they will cover the plate with a fairly large aperture, say P/11. Wide angle lenses, as a rule, work at too small an aperture. It is now generally accepted that the most suitable focus for a quarter-plate hand camera is from five to six inches A shorter focus than this means an exaggeration of the size of near ob- jects, whilst longer foci, because they give larger images and thert-fore give relatively greater movement of the image for the same period of time, require the shutter to work quicker. The shutter is a very important part of the hand camera for upon this depends to a great extent the success of the work. The number of patterns, sizes, prices, etc., of commercial shutters is very bewildering, and the speed at which some of them work, or are said to work, simply astounding. It will be impossible to enter into any description of the various types of shutters. In deciding upon which shutter to have, if it is a question of its speed, regard must be paid to the work for which it is re- quired; if we merely want to take street, beach, and ordinary scenes, in which there will be no very rapid movement, then it will he absurd to pay the necessary price to obtain a shutter which will work at one-thousandth of a second; on the other hand, if we want to obtain satisfactory results of the finish of horse races, athletic sports, etc., it will be absurd to try with a shutter which will not work at a greater speed than about one-hundredth of a second, I'or ordinary work such as will be met with in most town and country streets and roads about one-twenty-fifth to a thirtieth of a second will be quite quick enough; it is only when very rapidly moving objects are met with that very high speeds are required. 176 A B C of Photography. For very rapid work the best shutter is one, in my opinion at least, which works close in front of the plate and which is known as the focal plane shutter, and which consists of a blind of black cloth in which is an aperture which can be narrowed down or widened, thus allowing Jess or more light to reach the plate as the aperture passes rapidly across or down the plate. The rate of movement of the aperture can also be controlled. One important adjunct to the hand camera, and T consider it an indispensable one, is that known as the view finder. This may be defined as a small camera in which can be seen in miniature the objects which are in front of the lens of the real camera. There are various types of view finders, some which have a convex lens in front, the image from which is reflected by a small piece of looking-glass behind which is placed at an angle of 45° on to a piece of ground glass. The disadvantage of this form is that unless the ground glass is sunk considerably below the surface of the camera so as to be shielded to some extent from the light, it is extremely difficult to see the image. Another form has a concave lens with a mirror at an angle of 45° behind it, in this the image can be seen in a brilliant light, but unless the concave lens is marked in the centre with a cross or small spot, and the mirror is marked in the same way, there is the possibility of seeing to some extent a differ- ent view to that which is projected upon the sensitive plate, because the view alters with the inclination of the head. The two crosses are provided to obviate this; and in using this form of instrument, the principal object, or its image rather, which it is required to photograph, should be made to fall on the two crosses. Yet another form consists of two convex lenses, one in front of the image, from which it is received by the mirror and thence directed to the second lens, which presents it to the eye very brilliantly. Whatever finder is used, care should be taken to see that the image presented by it is exactly the same as that given by the lens on the plate; and to test this the best way is to set the camera up on a table by a window and expose a plate, taking Hand or Detective Cameras. 177 care not to move the camera after doing so, or if this is ab- solutely necessary, marking in pencil the exact position of the camera. Then developing the plate, fixing and washing and examining the image given by the finder with that on the negative. If the two do not coincide, and frequently they do not, it will generally be found that the finder includes rather more subject, in which case some black paper should be stuck on the finder, or black varnish used so as to block out all the view which is not included on the plate. If this be once done the two views will always agree. Hand cameras are also divided into two classes from another point of view that is, whether they have a so-called fixed focus or can be use;l for focussing. With the so-called fixed focus cameras all objects beyond a certain distance, are always in locus, and this distance depends upon the focal length of the lens and the aperture at which the lens works. There are several rules to find this distance, which rules are applicable to all lenses no matter of what focus or type they may be. One of the sim- plest and best rules is the following: Multiply 100 by the fraction expressing the diameter of diaphragm and by the square of the focal length and add half the focus. To make this quite plain we will take an example or two: Find the fixed focus, or that point beyond which all objects will be sharp with a 5-inch lens working at F/8:— then 100 X F/8 X 52 = 100 X Vs X 25 z= 26 ft. If the lens works at F/11, we shall have 150XF/11 X 52 zz 100 X 1/11X15 iz: 19 ft. If we use a lens of 6 in focus with F/8, the distance will be 371/2 ft. and with F/11 it will be 27 ft. It will be seen from this why short focus lenses are more convenient for hand camera work. A very simple method to obtain the necessary points to place the lens for any given distance is the following. Set up the camera, focus the clouds, and mark on the baseboard near the camera front at any convenient place which can be accurately determined again ; for instance, level with the front surface of the lens front. Then focus on an object 5 feet off, and again mark the base board; we shall then have two marks, one which 178 A B C of Photography . is called Distance'' nearer the back of tbe camera than the other. Half way between these two will be the focus for ol)jects ten feet off, half way between the ten foot mark and the distance mark will be the focus for 40 feet and so on. If these marks are found out. and plainly marked in figures there will be no difficulty in placing the lens at the required position for any given distance. It is extremely difficult, at first to judge correctly of the distance of any given object, but this is soon acquired with a little practice, and it is just as well to practise the estimation of distance and see by actual measurement whether the guess is right or not. There is a small instrument called the telemeter, which was su^yiested in France some years ago, but has only lately been placed on the English market at the author's sugges- tion, this will be found of great convenience in hand camera work. Some workers always adhere to fixed focus cameras, and they certainly have the advantage that there is one operation less to trouble abimt; on the other hand they limit the work to a great extent, and for this reason, personally, I prefer a focussing hand camera, and farther I prefer that type of camera in which there is a finder the full size of the plate, on which is seen an exact duplicate of the image which is thrown on the plate. Some hand cameras are provided with every convenience to be found in the ordinary camera, such as swing back, rising and falling front, long extension, etc., and whilst the addition ol such movement necessarily renders the camera rather less compact and dearer, they most certainly enable it to be used for ever\ kind of work, such as architecture, copying, portraiture, etc., so that the camera becomes a combined hand and stand camera. Some hand cameras are provided with levels let flush into the top of the box, the purpose of which is to enable the operator to see when he has his camera straight and not tipped up or down or sideways They are a refinement, but will certainly be found to fulfil the purpose for which they are designed, and prevent the too-olten-met-with appearance of houses falling down, or water running uphill. CHAPTER XX XII I. Instantaneous Work. Por instantaneous work with large or stand cameras it will of course be necessary to use a shutter, it is not possible to give much less than one quarter of a second with the cap, and there is considerable danger even with this of shaking the camera. For ordinar}^ landscape work in very brilliant light, and also for seascapes, beach and similar scenes, a sliutter will be found an advantage. One very good type of shutter which can be used to give time exposures also, is that known as the window- blind type and really consists of two pieces of ebonite or wood, fastened together in such a manner, that when one is down, covering the aperture of the lens, the other is above it. Two cords, one on either side, fastened one to each piece of ebonite, enable the one to be raised and the other to be lowered. With this shutter, which is not expensive, exposures of less than about one-twentieth of a second are ditficult if not impossible to give. For more rapid work another shutter must be obtained; one of the most general and simplest is the roller blind, which fits on the lens, with which both time and instantaneous exposures can be given, ranging in duration fra-m any length of time up to about one-ninetieth of a second. For ordinary work, we need not use such enormously high speeds, as already stated when speuking of hand cameras. Poss- ibly the f«dlowing information may not be out of place here. The nearer we are to moving objects, the shorter must be the exposure; the longer the focus of a lens, the shorter must bs the exposure; further, if the object is moving across the axis of the lens, that is, -parallel to the plate, the exposure must ob- viously be shorter than when the object is moving: away from or to the lens. Of course the more rapidly an object is moving the greater will be the, movement of its image on the ground glass. It will be seen from the above, that primarily, the neces- sary speed of the shutter depends upon the rate the object is / 1 8o A B C of Photography. moving and tlie distance of tlie object from the lens, so tliat the following tables will be useful as showing what can and what cannot be done: A man walking A vessel travellino; A trotting horse A galloping horse A train at J5 JJ J5 An object moving 3 miles per hour moves 4 „ 9 knots 12 „ 17 „ 20 „ 88 „ 60 „ 1 mile per hour moves 2 miles 4 „ 5 „ 10 „ 35 „ 20 „ 50 „ 100 „ . 150 „ , 41/2 ft. p. sec. 6 „ 15 „ 19 „ 28 „ 35 „ 39 „ 50 „ 59 „ 88 „ IV2 „ 3 „ 6 „ 71/2 „ 15 „ 221/2 „ 30 „ 73 „ 147 „ 220 „ To find the distance moved by the image on the ground glass, multiply the focus of the lens in inches by the distance in inches moved by the object in one second, and divide the result by the distance of the object in inches. Example: Find the movement of image on ground glass of an object moving 20 miles an hour with a lens of SVg-in. focus, and the objects 50 yards distant. 81/2 X 348 1800 = 12/3 inch per second. To find how quickly a shutter must act to take an object in motion, that there may be a circle of confusion less than 1-1 00th of an inch, divide the distance of the object by one hundred times the focus of the lens; and divide the rapidity of motion of object in inches per second by the result, when you will have Instant aiieous Work. i8r tli^ longest duration of exposure in fraction of a second; example : Kei^uired the speed of shutter tot ake an object moving 20 miles per hour with a lens of SVs-io- focus, the object bring 50 yds. distant. The object moves 29 ft. zz 348 ins. per second; 1,800 distance of object (8-5 X 100) zz 36 then 348 -f- 36^^^— 164 or of a second. Of course when it comes to working with a hand camera or in the field, no one will stop to work out any sums, but a careful consideration of them and working out a few examples will enable one with a very little experience to know what is possible and what is not. When using a hand camera for taking any * snap shots,' as they are called, of people, it is advisable to do so in as unostentatious a manner as possible, as by doing this you avoid letting them see that you are about to photograph them, and therefore you will secure them in more natural attitudes, as the beauty of such work lies in obtaining representations of the people in natural and unaffected attitudes. Animals are not quite so diffident as human beings and it is frequently possible to obtain snap shots of an animal or groups of animals in very natural positions, unless perhaps one inquisi- tive cow or sheep looks up to see what you are about. For obtaining good photographs of horses, etc., it is often necessary to secure them in an attitude showing off some particular point, this of course must bq attended to; but, as a rule, even then, it will be far better to have the animal at attention and looking round at the camera, and this can usually be secured by making some sharp and sudden sound just when you are ready to expose. Thus a smart tap on something hard, a quick shrill whistle, or some such noise will be quite sufficient to attract the attention of a horse or dog and make them turn slightly or prick their ears. As instantaneous work is done, experience will be gained and little dodges and tips will be learnt together with result of better work. In this branch, as in most others in photography, expe- rience is the best master. CHAPTER XXXIV. Photography in natural Colours. Naturally everybody will wish to make photographs in naturrJ colours, and whilst not an impossibily, it is by no means the easiest process in photography. There are three methods, which I will describe. The first is by using silver paper or silvered plates, but the results are not very satisfactory nor are they permanent. Good, writing paper shonld be floated on the surface of a 5 per cent solution of salt foi* five minutes, then dried and floated for three minutes on a 5 per cent solution of silver nitrate, allowed to drain, and again floated on a 5 per cent solution of salt, then well washed and immersed in the following solution, in diffused daylight, till it turns a blue green colour. Zinc chloride 11/2 grs. Sulphuric acid 20 drops. Water 25 drachms. The paper should then be w^ashed, blotted off between blotting paper and immersed in the following solution : Potassium bichromate 65 grs. Copper sulphate 65 grs. Add water 1 oz. then dissolve Mercury nitrate 65 grs. in as little water as possible, to which one or two drops of nitric acid have been added, and pour into the above hot solu- tion and allow to cool, when cold filter and make the bulk of the solution up to 1 oz. The paper must be immersed in this for half a minute, allowed to drain well, and then immersed in a 3 per cent solution of chloride of zinc till it turns blue, then well washed, blotted off* with blotting paper and exposed whilst damp. If paper thns prepared is exposed under coloured slips of glass or a painted lantern slide or transparency, quite satisfactory reproductions of the colours will be obtained, though the yellow Photography in natural Colours. 1 83 ani\ green only will be really satisfactory. To improve tlie other colours, these two should be covered with varnish, and the print placed io a bath of two per cent sulphuric acid and moved about, when all the colours will show. As already stated the colours are not permanent and will very quickly fade, or the whole print become black, if exposed to light. They may be made more permanent by being soaked in the mercury bath, well washing, placing in the chloride of zinc solution, then well wash- ing, drying and giving the print a coating of gnm arabic in five per cent sulphuric acid. This process, which was suggested by Kopp of Germany, is merely one of many such processes, all of which have the disadvantage of yielding results not permanent to light. In 1891, Professor Lippmann of Paris discovered a method of producing photographs in colours which has been most success- fully tried by many, and whilst it is rather a process for an expert it will not be out of place to give the method by which the results can be produced. To see the colours it is essential that the picture be viewed by brilliant reflected light, not by looking through the plate. It is impossible also to reproduce the pictures; therefore to make, say a dozen pictures, it is neces- sary for the sitter or object to be taken a dozen times, and as the exposure is somewhat long, this process is not a commercial possibility at present. A brief sketch of the necessary procedure may elucidate the matter before entering more fully into the details. A sheet of glass coated with a very transparent emulsion is placed with the film in contact with a reflecting surface, such as mercury, and exposed in the camera. On development an image is obtained, which when fixed, washed and dried shows all the colours of the original object. The silver is deposited in very thin layers, the distance between the particles of silver being extremely minute, being in some cases only one seventy-eight- thousandth of an inch. Upon the deposition of the silver part- icles at the correct distances apart depends the correct repro- duction of the colours. It will therefore be obvious that the process is an extremely delicate one. 1 84 A B C of Fkotogj^aphy. The emulsion necessary for this work is made from the following formula. A. Distilled water 1 oz. Gelatine 15 grs. Silver nitrate 9 „ B. Distilled water 1 oz. Gelatine 20 grs. Pot issium bromide 7V2 The gelatine in both cases is allowed to soak in the water for two hours, then melted by heat, the salts added, and when the solutions have cooled to 35° C. in the dark room, solution A is added to solution B with constant shalang. The emul- sion is then poured into a quart of alcohol and the mixture well stirred, and the particles of emulsion will collect on the glass rod used for stirring. They should be well washed for a short time in ruiining water, placed in a beaker and sufficient distilled water added to make the total bulk measure 2 ozs., and then a very gentle heat applied till the particles melt,. The emulsion which is almost transparent is now coated on glass, and as thin a coaling as possible obtained by rapidly whirling the plate round. It should now be bathed for two minutes in a mixture of Cyanine IV2 gr. Chinoline red , . ... 15 grs. Alcohol 550 minims. and again dried. The plate when dry is exposed in a special dark slide, the glass being placed next the lens and the film being in contact with mercury, which must be chemically pure. The exposure varies from three to fifteen minutes, and the developer is com- posed as follows; A. Pyro 4 grs. Nitric acid 6 drops. Distilled w^ater 1 oz. Photography in naUwal Colours, 185 B. Ammoniam sulphite 12 grs. Potassium bromide 10 Ammonia (Sp. Gr. 0^ 91) 14 minims. Water 1 oz For use mix 14 parts of water, 3 parts of B and 1 part of A. Fixing may be effected either with h^^po or a 2 per cent solution of potassium cyanide. After well washing the plate is dried, and when held at an angle, the colours, if all the operations have been successfully performed, will be distinctly visible. The third method of producing photographs in natural colours is what is termed an indirect process, and is applicable either to lantern projection, for use in an instrument which can be used by one person, as in the old form of stereoscope, or by a slight modification the resulting negatives can be used for making printing blocks or plates which can be printed in an ordinary printing machine, and a very large number of proofs be struck off which may be used to illustrate books and periodicals etc. This process is somewhat complicated, but is easier by far than that of Lippmann's just described. Coloured screens are used in conjunction with isochromatic plates, and from the resulting negatives the transparencies or printing surfaces are prepared. The coloured screens are usually made of aniline dyes dissolved in collo- dion or gelatine, and are placed between the lens and sensitive plate. "We will suppose that we have to reproduce in colours three small squares of red, yellow, and blue as in Fig. 22. Fig. 22. We use first of all a deep orange red screen with a plate sensitive to red and yellow, the resulting negative will give us the red and yellow squares opaque, whilst the blue will be clear glass as shown in Fig. 23, because the orange screen pre- vents the blue from acting on the plate. i86 ABCof Photography Fig. 23. If a green screen is used, the red square will be represented by clear glass and the other two by a dense deposit as shown in Fig. 24. Fig. 24. If a violet screen is^ used the yellow square will be bare glas3 and the other two will be opaque as in Fig. 25. Fig. 25. If from these transparencies are made and projected by means of three lanterns, using red, green, and violet glasses in the lanterns, we shall have a reproduction of the colours on the screen. And further, if the negatives are used to make printing surfaces or blocks, and the block printed from the negative made through the orange screen is printed in blue ink, and the block from the nega ive through the violet screen printed in yellow, and the block from the negative through the green screen printed in red, we shall obtain a faithful reproduction of the original. Although for illustration only three simple colours have been taken, the intermediate colours, orange, green and violet will be formed in precisely the same way, and so will all the innumerable number of tints which are met with in nature. C II A P T E R XXXV. Iron and Uraniam Printing. We have considered hitherto the use of the salts of silver and an inert powder in combination with bichromated gelatine and the salts of platinum for printing, but it is possible to use a good many other metallic salts for obtaining prints. The most commonly nsed are the salts of iron and uranium, and the necessary manipulations are simple and the salts by no means costly. THE FERRO-PRUSSIATE OR CYANOTYPE PROCESS. The resulting prints prepared by this process are of a bright blue colour and for rough proofs or moonlight or seascape scenes this colour is not unsuitable, though hardly suitable for portraits or views as a rule. A good smooth drawing paper should be chosen and pinned to a drawing board or other flat surface, and then coated with the following solution with a blanchard brush as previously described. No. 1. Potassium ferrid cyanide. Distilled water 75 grs. 1 oz. No. 2. Ammonio- citrate of iron, Distilled water 96 grs. 1 oz. Potassium ferridcyanide is known as red prussiate of potash. When the crystals have been weighed out they should be placed i88 A B C of Photography, in a measure, about half an ounce of water added, and well and quickly stirred and the water poured off ; then the ounce of distilled waler should be added and the crystals dissolved. Am- monio-citrate of ir 170 „ „ 2 „ 50 „ 20 „ 340 40 „ 30 „ 510 „ „ 1 ounce 0 draclim 30 min. 40 „ 680 „ » 1 „ 3 20 „ 50 „ 850 „ „ 1 n 6 10 60 „ 1020 „ „ 2 „ 1 0 „ 70 „ 1190 „ „ 2 „ 3 50 „ 80 „ 1360 ,> „ 2 „ 6 40 „ 90 „ 1580 „ » 3 „ 1 30 „ 100 „ 1700 „ „ 3 „ 4 20 „ THE CONVERSION OF FRENCH INTO ENGLISH WEIGHTS. Altbougb a gramme is equal to 15*4346 grains, the decimal is one which can never be used by photographers ; hence in the following table it is assumed to be 152/^ grains, which is the nearest approach that can be made to practical accuracy: 1 gramme 152/5 grains. 2 304/5 „ 8 46V5 . 4 61% „ .... drachm 1^/5 grain. 5 77 „ . . „ 1 17 grains. 6 922/, „ .... . „ 1 7 1074/5 ... „ 1 8 1231/5 ., ... ■ „ 2 „ 31/g „ 9 1383/5 „ ... ■ „ 2 „ 183/5 10 154 . „ 2 .. 34 „ 2 I 2 A B C^'Of Photography . 11 gramme = 1692/- grains. .. . qj. 2 drachm 492/^ grains. 12 „ = 1S4-4/5 ., ...... 3 „ 44/5 „ 13 „ = 2001/5 „ .... „ 3 „ 201/5 „ 14 = 215^5/5 . . . • „ 3 „ 853/5 „ 15 „ =^ 281 , „ 3 „ 51 16 „ = 246-V5 „ „ 4 „ 62/5 „ 17 „ =. 2614/5 „ .... „ 4 „ 214/5 „ IS „ = 2771/5 : 4 „ 371/5 „ 19 „ =: 292-3/5 „....„ 4 „ 533/^ 20 „ = 308 „ 5 8 - 30 „ 462 . . . „ 7 „ 42 40 „ — 616 „ „ 10 „ 16 50 „ = 770 „ . . . . „ 12 „ 50 „ 60 „ = 924 „ „ 15 „ 24 70 „ = 1078 17 „ 58 80 = 1232 „ „ 20 „ 32 90 . „ = 1386 „ .... „ 23 -„ 6 100 „ 1540 „ „ 25 „ 40 CONVERSION OF GRAINS AND OUNCES INTO GRAMMES. Grains Grains 0 an res to the Ounce =z to Graaimt's. to Grammes. Grammes to 100 cc. 1 0-06479 28-3495 0-22817 2 0 12958 56-9660 0-45635 3 0-19437 85-0485 0 68452 4 0-25916 113 3980 0-91 26^ 5 0-32395 141-7475 1-14086 6 0-38874 170-0970 1-36904 7 0-45353 198-4465 1-59721 8 0-51832 226-7960 1-82533 9 0 58311 255-1455 2 05356 Metric System of Weights and Measures, 213 ft CD +5 M 73 Cfi CC 03 . . . s S ? S S S O f- (M CO ^ b lo 1-5 * O CI r-l (M a a a a (T) O . 13 rj fii O O X> H H w5 . O O ^ O O o 0) a| 2 o OOOOOOrHOOO OOOOOiH '-'OO OOCOi-1 rlj'-''^ O" O" O" r-T tH 7' O O r-( tH 2 a ; ill ^ d q; cu ;h 0) 0) ^ ft 15 S ^Si §a ei c« f3 c3 . t~ i-< O kO CO t- rjH 10 CO t- •M p CO 00 (M ^5 a ^ o ^ g ^. _ - ., .2 t .2 .S? _ V2 . e3 .X) 5 2 PS S E E ^ !^ y ,Q o O O a a pi PS O C3 O O o ^ « 5 s^as^ 00 O rH O O O 00 o O WW ABCof Photography, o fl • • • . _= «! M ai Cfl 0 O) o . . ^ A ^ A A a g ^ .s .s .s .s .s CO CO 1^ CO C3S . - - CO 35 CO cq p ^ t- CO G5 CO p ' CO CO ci CO * H ;H ' 0) <1» OJ 0) 1) ! a s a a a s O O 1— I c3 c* o o o 5 5 5 o o o iH O O JL o a 0^ a d • s a ^ I al I i.§| a se. "a 9 5 c« CO !» > t- 03 CC . ;h ^ ^ O) a> 0 -tJ -u 03 5'*"^03riCOiXia) So a; 03 o 2 ^5 o--^ 5^ a +3 S > - ^§ °H ^.c b o ^ 2 H ^2 ^-^-go^a:^ ?5 O ^ .S " % O uA'^'^^ 0% ^ CD O) -2 o c ft) a; ^ o ?; 2 ^ o g ai^ ft, -M .3 o 4i; -fj . -r; J ^ o o M t o o c3 a; 0) d c rd ^ Useful Tables of Reference, 215 USEFUL TABLES OF REFERENCE FOR PRACTICAL PHOTOGRAPHER?. Compiled from various sources. TABLE SHOWINO DISPLACEMENT ON GROUND GLASS OF OBJECTS IN MOTION. By H E N K Y R. T O L M A N , (Republished with corrections, from the Photographic Times.) Lens 6in. Equiv. Focus, Ground Glass at Principal Focus of Lens. Miles er Hour. Feet per Second. Distance on Ground Glass in Inches, with Object bame with ^jDjecu 60 feet away. bame with \j Djec u i^u leei away. 1 IV2 •29 •15 •073 2 3 •59 •29 •147 3 4V2 •88 •44 •220 4 6 ri7 •59 •298 5 7V2 1^47 •73 •367 7 9 r76 •88 -440 0 101/2 2-05 1-03 •513 8 12 2^35 ri7 •587 9 13 2^64 1-32 -660 10 I4V2 2-93 1-47 •733 11 16 3-23 1 61 •807 12 17 V2 3^52' 1-76 •880 13 19 3-81 1-91 •953 14 2OV2 4-11 2-05 1-027 15 22 440 220 rioo 20 29 .5-87 2 93 1-467 25 37 7'33 367 1-8:^3 30 44 8-80 4-40 2- 200 35 51 10 27 5.13 2 567 40 59 11-73 5.97 2933 45 66 13'20 6-60 3-300 50 73 1467 733 3-667 65 80 16^13 8-06 4-033 60 88 17*60 8.80 4-400 75 110 22-00 iroo 5-500 100 147 ' 29-33 14-67 7-333 125 183 36-67 18-33 9167 • 150 220 44-00 22-00 11-000 2l6 A B C of Photography CONVERSION OF MINIMS, DRACHMS, OUNCES, AND PINTS TO CUBIC tJENTIMETRES AND LITRES. Minims Drachms Ounces Pints to c.c. to c.c. to c.c. to Litres. 1 0 05916 3-5495 28-396 0-56792 2 0-11832 7-0990 56-792 M3584 o o U 1 / /4(5 1 n . A /I Q K lU o4oo Q K.I QQ 1 70d7o 4 0-23664 14-1980 113-584 2-27168 5 0-29580 17-7475 141 980 2-83960 6 0 35496 21 2970 170-376 3-40752 7 0-41412 24 8465 198-772 3-97544 8 047328 28-3960 227*168 4-54336 9 0-53244 31-9455 255-564 5-11128 RELATIVE EXPOSURES FOR VARYING PROPORTIONS OF IMAGE TO THE ORIGINAL. [The following paper was r(3ad before the Photographic Society of Great Britain by Mr. W. E. Debenham. Its usefulness would be diminished by abbreviation, hence we reproduce it in fall. — Ed.] When an enlarged photograph has to be made, either fi'om a negative or print, it is commonly understood that the greater the degree of enlargement the longer will be the exposure required, but I have generally found only the vaguest ideas to exist as to the amount by which such exposure has to be prolonged. Sometimes, indeed, it is assumed that the exposure will be in direct inverse proportion to the area covered, so that a copy of twice the linear dimensions of the original — covering, as it does, the area of four times the size — would require an exposure of four times that sufficing for a copy of the same size. This calcula- tion, however, omits to recognise an important factor, and leads Relative Exposures etc. to serious error; the actual exposure required in the case men- tioned (assuming the same lens and stop to be used) being not four times, but two and a quarter times, that of a copy of same size; whilst, when we come to high degrees of enlargement, the error would amount to an indication of nearly four times the exposure actually required. To find the relative exposure, add one to the number of times that the length of the original is contained in the length of the image, and square the sum. This will give the figure found in the third column of the^ annexed table. Proportion of iiuaii't^to original (linear). Distance of image from leDS * in terms of principal focus. Proportionate exposures. XJ\V} OUiCO |Ji(J~ I'knT'f"! nn Pn \t\ fTio'f ictjuiicu. lor 1 ► Q55TY1P Gl VP 11/30 1-07 •27 IV20 110 •28 IVio 1-21 •3 IVs 1-27 •31 Vg IVe 1-36 •84 11/4 1-56 •39 IV2 2-25 •56 13/4 306 •76 (Same 1 2 4 1 size) 2 3 9 2-25 3 4 16 4 4 5 25 6-25 5 6 36 9 G 7 49 12-25 7 ■ 8 64 16 * With a double lens it is usually sufficient to measure from the position of the diaphragm plate. 2l8 A B C of Photography. RELATIVE EXPOSURES FOR VARYING PROPORTIONS OF IMAGE. TO THE QKi^mkl..— (Continued.) 1 roportion image to orig (linear). 01 inal Distance of image from lens * in terms of principal focus. Proportionate exposures. Exposures pro- portioned to tliat required for copying same size. 8 9 81 20-25 9 10 100 25 10 11 121 30-25 11 12 144 36 12 13 169 42-25 13 14 196 49 14 15 225 56-25 15 16 256 64 16 17 289 72-25 17 18 824 81 18 19 361 90-25 19 20 400 100 20 21 441 110-25 21 22 484 121 22 23 529 132-25 23 24 576 144 25 25 26 676 169 26 27 729 18225 27 28 784 196 28 29 841 210-25 29 30 900 225 80 31 961 240-25 * See i^age 217. Relative Exposures etc. As examples: suppose a copy is wanted having twice the linear dimensions of the original. Take the number 2, add 1 to it, and square the sum, 32—9. Again, if a copy is to be of eight times the linear dimensions of the original, take the number 8, add 1, and square the sum, 92=81. Copies respect- ively twice and eight times the size (linear) of the original will thus require relative exposures of 9 and 81 — i. e.y the latter will require nine times the exposure of the former. It is convenient to have a practical standard for unity. An image of the same size as the original is a familiar case, and serves as such standard. By dividing the figures in the third column by four, we get at the figures in the last column, which represent the exposure required for varying degrees of enlarge- ment or reduction, compared with the exposure for a copy of the same size. The table is carried up to enlargements of thirty diameters ; that is about the amount required for enlarging a small carte- de-visite to life size. The exposures required in reductions do not vary at all to the same extent that they do in enlargements, It has, therefore, not been thought necessary to fill in the steps between images of l/io "^/20' between I/oq and 1/39 of the size of the original. Beyond 1/30 there is scarcely any perceptible difference in the exposure until disturbance comes in from another cause, a considerable distance of illuminated atmosphere (haze or fog) t-^ intervening. The figures in the second column will also serve as a table for distances from the lens to the plate and to the original, all that is necessary being to multiply by the principal focus of the lens in use. In the case of enlargements the figures less than 2 must be multiplied to get the distance from the original to the lens, and the figures greater than 2 for the distance from lens to image. For reductions, the figures less than 2, multiplied by the principal focus of the lens, yield the distance from Jens to plate; and the figures higher than 2, similarly multiplied, give the distance of original from lens. 2 20 ' A B C of Photo grapJiy . TABLE SHOWING COMPARATIVE VALUE OF ALKALINE Commercial Name. Chemical Symbol. NaHO Na2C03 N:.HC03 j Sodium Carbonate, x Sal Soda Crystals, J Sodium Bicarbonate 1 Sesqui-carbonate of Soda," ^ Equal work is done by 80 parts of Caustic Soda, 286 parts of bonate of Soda. These quantities must be increased to make up for the usual percentage of impurity given in the above table may be Potassa (Caustic Potash) Potassium Carbonate. \ Carbonate of PotassT, [ Sal Tartar, | Saleraius, J Potassium Bicarbonate, \ Bicarbonate of Potassa, / KHO K2CO3II/2H2O K2CO3 KHCO3 Equal work is done by 112 pnrts Caustic Potassa, 165 parts (about) quantities must be increased in proportion to impurities, as noted the same amount of work when and when the one named in a substitute of proper strength and solubility, in the market. Comp Val. of AUzaline Carbonates in Developers. 221 CARBONATES IN DEVELOPERS. By 0. G. Mason. [Molecular Weight. The Commercial Salt contains of the pure Salt about 100 parts of 36 percent. Acetic Acid Require for Saturation. Solubility in Water (approximate) 40 80 to 92% 26.66 p'rts of 90% Soda 1 part in 2 286 yb to yo% by. 00 „ yo% J, 1 „ 2 106 84 About 98 to 99% 98 to 100% 1 89.88 of 98 to 99% \ dry Sal Soda. / 50.91 of 99% Bicarb, t Soda. }. ,. . }l „ 13 Sal Soda (crystals), 106 parts of Sal Soda (dry), 168 parts of Bicar- acy impurity contained in the sample being used; for this purpose assumed for all ordinary photographical uses. 56 80 to 95% f 37.33 parts of 90% \ Potassa. 1 1 part in 1 165 1 76 to 96% Usually about 81% f 51.11 parts of 81% \ Carb. Potassa. 100 About 95% 100% n 22.74 parts of 95% \ Carb. Potassa. 1 60 parts of 100% \ Bicarb. Potassa. i. ,. . }i 4 ordinary Carbonate Potassa, 209 parts of Bicarbonate Potassa. These ,in case of Soda. These two alkalies are interchangeable for doing ja. given formula can not be obtained the table may assist in choosing I Dry or anhydrous Carbonate of Potassium is not found usually 222 A B C of Photography. ELSDEN'S TABLE OF o Poisons. Remarks. Caustic Vegetabl Alkalies. Acids. Oxalic Acid. including Potassium Oxalate. Ammonia. Potash. Soda. Meecueic Chloeide. 1 dram is the smallest fatal dose known. Vapor of ammonia may cause iuflamraation of the lungs. 3 grains are the smallest known fatal dose. or Acetate of Lead. The sub-acetate is still more poisonous. ic Sail ' Cyanide of Potassium. a. Taken internally, 3 grs. fatal. Metall Bichromate of Potassium. h. Applied to wounds and ab- rasures of the skin. a. Taken internally. Nitrate of Silvee. h. Applied to slight abrasions of the skin Concentrat( Mineral Acids. NiTEic Acid. Hydrochloeic Acid. Sulphuric Acid 2 drams have been fatal. In- halation of the fumes has also been fatal. 1/2 ounce has caused death. 1 dram has been fatal. Acetic Acid, concentrated, has as powerful an efifect as the Iodine. Variable in its action; 3 grains have been fatal. Ether. When inhaled. Pyrogallol. 2 grains sufficient to Mil a dog. Els den's Table of Poisons and Antidotes, 223 POISONS AND ANTIDOTES. Charactertstic Symptoms. Hot, burning sensation in throat and stomach; vomiting, cramps, and numbness. Swelling of tongue, mouth, and fauces; often followed by stric- ure of the oesophagus. Acrid, metallic taste, constriclion and burning in throat and stom- ach, followed by nausea and vomiting. Constriction in the throat and at pit of stomach; crampy pains and stiffness of abdomen; blue line round the gums. Insensibility, slow, gasping respi- ration, dilated pupils, and spas- modic closure of the jaws. Smarting sensation. Irritant pain in stomach, and vomiting. Produces troublesome sores and ulcers. Powerful irritant. Corrosi'^n of windpipe and violent inflammation. mineral acids. Acrid taste, tightness about the throat, vomiting. Effects similar to chloroform. Resemble phosphorus poisoning. Antidote. Chalk, whiting or magnesia, sus- pended in water. Plaster or mortar can be used emergency. Vinegar and water. "Wliite and yolk of raw eggs with milk. In emergency, flour pasLe may be used. Sulphates of soda or magnesia. Emetic of sulphate of zinc. No certain remedy; cold affusion over the head and neck most efficacious. Sulphate of iron should be ap- plied immediately. Emetics and magnesia, or chalk. Common salt to be given immedi- ately, followed by emetics. Bicarbonate of soda, or carbonate of magnesia or chalk, plaster of the apartment beaten up in water. Vomiting should be encouraged, and gruel, arrowi oot and starch given freely. Cold affusion and artificial respi- ration. No ceit.tin remedy. Speedy emetic desirable. 224 A B C of Photography, o P O m < O 3 .CM ^ ^ ^ +3 ^ E3 iillll ^ O 03 ^ o bcis If ^ o <=l , ^ . ^ T-l "t^ fcO CC M O (D p ^ d 2 o s s 4J o d ^ -S o g oj O OJ g r-; Q o sj fc-, O ^ (D S D c3 ...52 CO ^ ^ !i M O O n ^ •r o A-^ ;q =^ ^ o 0^ ^ ^ .2 S 0 o ■^"g ^-2 O O 2 s o o a ^ § d .■[a:^B.wjo saoano Grains. c-CMCX)l>^CO'^CMCO r-H ?d Gi Tf<05C0C0CMiOCOr— tCOCM 1— 1 t— 1 CM 'raH 05 r—t CO rH r—l aqi ^ a5|B^ .Ta|BAi JO saouno ping g qo^a .loj Grains. O ^ l O GOtr-iO'^CMirst^OCM CM QO' rH CO t-^ r-i )0 05 (—1 CM^«OOirHCM'*iO.rJt O CO O JO CO O CO CO t>l ,— I Tji CO CO xfi CO rH ?C i-HCMrfliOCOCOOt^rfiTff i-H -CMC01>-lO^GQQ0 lOr— 'COCMt—iOCOrHOSCM 05 CO* QO* CM lO QO* 1— 1 CO CM I— Ir-HCM -^COC^if— IQO f-H 1— 1 To make 1 per cent 2 per cent 3 per cent .... 4 per cent .... 5 pel* cent .... 10 per ceat 15 ner cent . . . . ! 20 per cent .... 25 per cent .... 40 per cent . . . . Preparing Percentage Solutions. 225 1^ <- (^{Bs gq:^ JO 95[b:^ .IG^'B^VL JO S9ouno W&'i aq:^ jo a5[B; .lai^BAi JO saouno f^BS 9q:^ JO 95[b; .T9;BiVi JO S9ouno pUl]J C qOB9 .10^ :^{BS 9Tj; JO 95[B:^ J9:)BM JO S90iino ppif qOB9 .lOJ :)|BS 9q:^ jo gj^B) .i9:^BAi JO S9onno :^[Bs 9q; JO 9>[b:^ J9:^BM JO S9onno :^[BS 9q) JO 95[b:^ .T9;bm jo 9ouno ping X -10^ C3 O GQlOC^iCO^OSCOCOr— ICQ GO ''Jfi «0 Gvi if5 I— J C5 GO I— I G i—J 10 10 r-^ CCi 10 r— 1 rHrH<>iTf(05Q0lOr-H p-H OS GO £>- 10 t^iOCsOSOSOOC^rftiLO 10 rH »0 f—! i>l I— I C5 10 GO O cJ 10 rH CO ^* CD 05 CO* Cd' CCi CQ rji rH CO CO CD r-H CO r-< Cvi >0 CDCOl— (iOCOL^'^OO'-HCQ CO 10 GO -Tf(00O )Or-HCOrHl:^lOr— IG--^ rH -H TjH oi 06 iO r-H rH Tf( C5 _ O O O O OOOOOOOlOO ^'^i.OTPCOC-H.-li-IC 22 19 17 16 15 13 13 12 11 10 10 9 9 4^/. 27 23 21 19 18 16 15 14 13 12 12 11 10 10 5 30 27 24 21 19 18 17 15 14 14 13 12 11 10 51/4 33 29 25 23 21 20 18 17 16 15 14 13 13 12 37 31 29 26 23 22 20 19 17 16 15 15 14 13 5^/. 39 34 31 28 26 24 22 20 18 18 17 16 15 14 6 43 38 33 31 28 26 24 22 21 20 18 17 16 15 6V4 47 41 37 33 30 28 26 24 22 20 20 19 18 17 6I/2 50 45 40 36 33 29 28 26 24 23 21 20 19 18 6=^/. 55 48 43 39 36 32 30 28 25 24 22 22 21 20 7 58 52 45 42 38 35 31 30 28 26 25 23 22 21 DR. J. J. HIGGINS S TABLE. Equivalent Focus. fl5 r/6 fn ri9 riio V/ll /•/12 //14 ni5 42 35 30 26 23 21 19 171/2 16 15 14 5V2 „ 6 „ 50V? 42 36 32 28 25 23 21 19 18 17 60 50 43 38 34 30 27 25 23 21 20 6V2 „ 70V0 59 50 44 39 35 32 291/2 27 25 23 V2 7 „ 82 68 59 51 45 41 39 34 31 29 V- 27 Calculated for a Confusion Disc of less than of an inch. Enlargements . ENLARGEMENTS. I'rom the British Journal of Fhotography Almanac. TIMES or ENLARGEMENT AND REDUCTION. Inches. 1 Inch. 2 Inches 3 T U Inches. 4 Inches. 5 Inches. 6 Inches. 7 Inches. 8 Inches. 4 4 6 3 8 2^/4 10 2V? 12 2=^/5 14 2V3 16 2^/7 18 21/4 2V2 5 5 7V2 . 3\ 10 3V3 12^2 15 3 171/2' 20 2«/, 221/9 2^^/.6 3 6 6 9 41/2 12 4 15 3\ 18 21 31/2 24 27 3^/8 3V2 7 7 8 8 lO'/o 51/4 14 17 V2 43/4 21 241/2 28 4 311/9 3^^/ie 12 6 16 5V4 20 5 24 ^% 28 4^'3 32 36 4V2 4V2 9 9 I3V2 18 6 22V2 5^/8 27 5^/5 31 1/2 51/4 36 5V7 401/2 10 10 15 71/2 20 6^/3 25 6V4 30 6 35 40 45 5^/8 5V'2 11 11 12 12 I6V2 8V4 22 271/2 7^/8 33 6V2 381/5 44 6=^/7 491/2 6^/.6 18 9 24 8 30 7V9 36 7^6 42 7 48 6«/, 54 14 14 21 IOV2 28 35 8^/4 42 8^/5 49 8^6 56 8 63 7^/8 8 16 16 24 12 32 10"^/3 40 10 48 9^/5 56 9^3 64 9V7 72 9 18 18 27 131/2 36 12 45 11 V4 54 lo'-Zs 63 101/2 72 10^/, 81 lOVs The object of this table is to enable any manipulator who is about to enlarge (or reduce) a copy any given number of times, to do so without troublesome calculation. It is assumed that the photographer knows exactly what the focus of his lens is, and that he is able to 9 230 A B C of Photography. measure accurately from its optical centre. The use of the table will be seen from the following illustration: A photographer has a cay'te to enlarge to four times its size, and ihe lens he intends employing is one of six inches equivalent focus. He must therefore, look for 4 on the upper horizontal line, and for 6 in the first vertical column, and carry his eye to where these two join, which will be at 30 — 7V2. The greater of these is the distance the sensitive plate must be from the centre of the lens; and the lesser, the distance of the picture to be copied. To reduce a picture any given number of times the same method must be followed, but in this case the greater number will represent the distance betw.een the lens and the picture to be copied; the latter, that between the lens and the sensitive plate. This explanation will be sufficient for every case of enlargement or reduction. If the focus of the lens be twelve inches, as this number is not in the column of focal lengths, look out for 6 in this column and multiply by 2, and so on with any other numbers. FREEZING MIXTURES. The following mixtures will be found useful where ice is not readily obtainable. Ingredients. Parts by Weight. The Temperature at starting being 50« Fahr. the ther- mometer sinks. Water Nitrate of ammonia , Water Salpetre Chloride of ammonium (sal ammoniac) Water Nitrate of ammonia Carbonate of soda Snow Chloride of sodium Snow Crystallised chloride of calcium Crystallised sulphate of soda... Hydrochloric acid From -h 50° to + 4:"" „ -l-50no4-10° „ -f50oto-|- 7° „ 32° to — . 50 „ +32" to— 50° „ -1- 50° to O'' Table of View-Angles . TABLE OF VIEW-ANGLES. By Clarence E. Woodman, Ph.D. (Photographic Times.) Divide the Base of the Plate by the Equivalent Focus of the Lens. If the The If the Ine 11 the The quotieot is angle is quotient is augle is quotient is angle is Degrees. Degrees. Degrees. •282 16 •748 41 1 3 66 •8 17 •768 4^ 1 .82 67 •317 18 •788 43 136 68 •335 19 •808 44 1-375 69 •853 20 •828 45 14 70 •87 21 •849 46 1427 71 •389 22 •87 A '7 4/ 145 72 •407 28 •89 48 1^48 73 •425 24 •911 4y 1^5 74 •443 25 •988 50 l'o8 75 •462 26 •954 51 1^56 76 •48 27 •975 159 77 •5 28 1" 53 162 78 •517 29 1*02 54 1^649 79 •586 30 1041 55 1-678- 80 •55 5 31 1068 56 1-7 81 •573 32 1086 57 1-739 82 •592 33 1^108 58 1-769 83 •611 34 1.132 59 1-8 84 •631 35 1-155 60 1-833 85 •65 36 1-178 61 1-865 86 •67 37 1-2 62 1-898 87 •689 38 1-225 63 1-931 88 •708 39 1-25 64 1-965 89 •728 40 1^274 65 2- 90 232 A B C of Photography . Example. — (j'w'Q'o. a lens of 13 inches equivalent focus ; re- quired the angle included by it on plates respectively 3 1/4 X 4I/4, 41/4X61/2, 6I/2X8I/2, 8X10, 10X12, and 11X14. 1. Dividing 4 25 by 13, we have as quotient '327 — midway between the decimals -317 and "333 of our table; therefore the required angle is 18° 30'. Similarly — Degrees. 2. 6 6 -|- 13 — '5; corresponding to 28. 3. 8.5 13 — -654; „ „ 36. 4. 10 -i- 13 =1 -77; „ „ 421/2- 5. 12 ~ 13 -923 „ „ 491/2. 6. 14 ~ 13 = 108 „ „ 57. TABLE OF THE SYMBOLS, ATOMICITY, ATOMIC, AND EQUIVALENT WEIGHTS OF THE ELEMENTS. NA5IE Symbol and Atomicity. Atomic Weight. Equivalent Weight. Aliii 27-4 9-13 Sb"i 122-0 40-66 As'i^ 75.0 250 Ba" 137-0 68-5 Biiii 208 0 69-33 Biii 11-0 3-66 Bri 80-0 80-0 Cadmium Cdii 112-0 560 Csi 133-0 133 0 Calcium Caii 400 20-0 Carbon Civ 12-0 30 Ceii 920 460 Table of the Syinhols, eic. of the Elements. 233 TABLE OF THE SYMBOLS, ATOMICITY. ATOMIC, AND EQUIVALENT WEIGHTS OF THE ELEMENTS. - (Continued.) Symbol and Atomicity. Atomic Weight. EquivalcLt Weight. Chlorine Chromium Cobalt : Coliimbium (or Niobium.. . Copper (Cupru.) { Davy urn Didymium Erbium Fluorine Gallium Glucinum Gold (Aurum) Hydrogen Indium Iodine Iridium T /T? \ \ Ferrosum . . . iron (l^errum) <^ ^ ' \ I^erricuni. . . Lanthanum Lead (Plumbum) Lithium Magnesium Manganese Mercury (Hy- | Mercurosum. drargyrum \ Mercurieum. Molybdenum Nickel Nitroo-en Cli 35-5 35-5 Cr" 52-2 26 1 Coii 58-8 29 4 Cbv 94 0 18-8 Cui 68-4 634 Cuii 63-4 31-7 Da Diii 95-0 47-5 Eii 112-6 56 3 Fli 190 190 Ga 680 Gii 9-4 4-7 Aui^i 196 0 65-33 Hi 1-0 1-0 Iniii 113 4 37-8 li 127 0 1270 Iriv 198-0 49-5 Feii 560 28 0 Fe"i 56 0 18 66 Laii 92-8 46-4 Pbii 2070 103-5 Lli 70 70 Mgii 240 120 Mnii 55-0 27-5 Hg 200-0 200 0 Hg" 200 0 1000 Moii 920 460 Niii 58-8 29-4 N"i 14 0 4-66 234 A B C of Photography TABLE OF THE SYMBOLS, ATOMICITY, ATOMIC, AND EQUIVALENT WEIGHTS OF THE YAjY^yimT^.— (Continued.) Osmium Oxygen Palladium Phosphorus -m ,. f Platinosum. . . \ rlatmicum . . . Potassium (Galium) Rhodium Rubidium • . . . Ruthenium Selenium Silicium (or Silicon) Silver (Argentum) Sodium (Natrium) , Strontium Sulphur Tantalum Tellurium , Thallium Thorium (or Thorinum) . . , m- /ox \ Stannosum . Tm (Stannum < g Titanium Tungsten (Wollram). Uranium V anadium Yttrium .. . Zinc Zirconium ;annicum. . . Symbol and Atomicity. Atomic Weight. Osiv 199-0 49-75 0" 160 80 Pd" 106-5 53-25 piii 310 10-33 Pt" 197-4 98-7 Ptiv 197-4 49-35 K 89-1 391 Rhii 104.4 52-2 RV 85-4 85-4 Ruiv 104-0 26-0 Seii 79-4 39-7 Siiv 28-0 7-0 Agi 108-0 108-0 Nai 23-0 23-0 Sri 87-5 43 75 Sii 32-0 160 Ta'^ 182-0 86-4 Teii 1280 64-0 Tei 204-0 204-0 Thiv 231-5 57-87 Su" 118-0 590 Siiiv 1180 29-5 Tiiv 50-0 12-5 Wiv 1840 46-0 Urii 1200 600 Viii 51-3 171 Yii 61-7 30-8.> Zn» 65 2 32-6 Zriv 89-6 22 4 Uniform System^'' Numbers for Stops. 235 "UNIFORM SYSTEM'' NUMBERS EOR STOPS EROxM r/11 TO F/100. In the following table Mr. S. A. Warburton has calculated the exposure necessary with every stop from //I to /*/100 compared with the unit stop of the "uniform system" of the Photographic Society of Great Britain. The figures which are underlined show in the first column what f ja must be in order to increase the exposure in geometrical ratio from f l^, the intermediate numbers showing the uniform system number for any other aperture. / 11/4 1-414 IV2 13/4 2 U.S. No 2i/4 21/2 2-828 23/4 3 31/4 3 33/4 4 41/4 41/2 43/4 5 51/4 51/2 5 656 •097 1/8 •140 191 1/4 •316 •390 V2 •472 •562 •660 •765 •878 1.00 1^12 1-26 1 41 1-56 1-72 V89 2 / U.S. No. / U.S. No. 53/4 2 06 14 12-25 6 2^25 15 14^06 61/a " /4 2^44 IB 16 6I/2 2-64 17 18.06 63/4 2-84 18 20^25 7 306 39 22-56 < V4 328 on 25 00 71/2 3-51 21 27-56 73/4 3 75 22 30^25 8 4 22-62 32 ^V4 4.25 28 33 06 8 1/2 83/4 4-51 24 36 00 4-78 25 39-06 9 5-06 26 42-25 91/4 5-34 27 45-50 91/2 5.64 28 49 00 93/4 5.94 29 52-56 10 6-25 30 56-25 11 7 56 31 60 06 11-31 8 32 64 12 900 33 68 06 13 i 1056 34 72-25 236 A B C of Photography. UNIFORM-SYSTEM" NUMBERS EOR STOPS {Contd.) f U.S. No. / U.S. No. / U.S. No. 35 76*56 57 203 06 80 40000 36 81 00 58 210-25 81 41006 37 85-56 59 217-56 82 420-25 38 90-25 60 225-00 83 430-56 39 95 06 61 232-56 84 440 00 40 100-25 62 240-25 85 451-56 41 105-06 63 248-06 86 462-25 42 110-25 64 256 87 473-06 43 115-56 65 2(i4 ()6 4^\J^ \J\J 88 484-00 44 12100 66 272 25 89 495-06 45 126-56 67 280-56 90 506 25 45-25 128 68 289-00 t^\J U \J\J 90-50 512 46 132-25 69 297 56 91 51756 4.7 138 06 70 306 25 92 52Q-00 48 144 00 71 315-06 93 540'56 4.Q 150 06 72 82400 KJ T f/J, V16O s^^- V50 sec. 1/3 sec. U 1 u Vso s^c- 1/25 sec. ^/^ sec. V40 .V12 sec. 0 40 i\ 0. 0, or 1/ i i 0 1"* . . . . V20 sec. sec. 1 sec. 1 9r ATo 1 A /^T -f/l A 1/10 sec. 1/3 sec. 2 sees. InO. oiOj 01 ly^Ki' DBUoqji30 uiniuouixuv o •a^tJTioqjBQ uinipog • -r Oi Cft 51 to o Tt« f «o 2 uiniss8:joj uinruoiuuiv ; 61 M CO : « : CO 'M r 90 - O M 000 >rt vf5 U3 i« 'fT «9 ^aS^Sg-C-^^gSSSS I =;^•:22.?5S2b«cd Pyro gallic Developers . 243 e*5 CO o » 14 5> 15 20 J> 25 30 35 J» 40 >' 45 J J 50 )> ft. in 7 6 8 3 9 0 9 9 10 6 11 3 15 0 18 9 22 6 26 3 30 0 33 9 37 6 ft. in 6 0 6 7 7 2 7 10 8 5 9 0 12 0 15 0 18 0 21 0 24 0 27 0 30 0 ft. in. 5 0 5 6 6 0 6 6 7 0 7 6 10 0 12 6 15 0 17 6 20 0 22 6 25 0 fc. in. 4 3 4 9 5 2 5 7 6 0 6 5 8 7 10 9 12 10 15 0 17 2 19 3 21 5 ft. in. 3 9 4 2 4 6 4 11 5 3 5 8 7 6 9 4 11 3 13 1 15 0 16 10 18 9 ft. in. 3 4 3 8 4 0 4 4 4 8 5 0 6 8 8 4 10 0 11 8 13 4 15 0 16 8 Lanternists' Ready Reference Table. 245 LANTERNISTS* READY REFERENCE 'Ikm^Y^.— {Continued) Distance be- tween Lan- tern and Screen . lOin. FOCUS OF LENS, llin. 12m. 13in. 14in. 15in. DIAMETER OF DISC. It. in. it. in . It. in. It. in. It. in. ■ff It. m. lu leet. Q 0 n u 0 4j n y 0 4/ 0 9 0 lO 9 9 11 „ 3 4 3 0 2 9 2 6 2 4 2 2 12 „ 3 7 3 3 3 0 2 9 2 7 2 5 13 „ 3 11 3 7 3 3 3 0 2 9 2 14 „ 4 2 3 10 3 7 3 3 3 0 2 9 15 „ 4 6 4 1 3 9 3 6 3 3 3 0 20 „ 6 0 5 6 5 0 4 7 4 3 4 0 25 „ 7 6 6 10 6 3 5 0 5 4 5 0 30 „ 9 0 8 2 7 6 6 11 6 5 6 0 35 10 6 9 6 8 9 8 1 7 6 7 0 40 „ 12 0 10 iO 10 0 9 2 8 6 8 0 45 „ 13 6 12 3 11 3 10 4 9 8 9 0 50 „ 15 0 13 8 12 6 11 6 10 9 10 0 Examples. — An 8in. focus lens at a distance of 35ft. will give a disc of 13ft. lin. To produce a disc of 12 ft. with a lens of lOin. focus, the lantern and screen must be separated by 40 ft. To produce a disc of 15ft. at a distance of 45ft. will require a lens of 9in. focus. EQUATIONS RELATING TO FOCI, &c. The following simple optical formuhe and calculations, worked out by Mr. J. A. C. Branfill, will prove useful in many branches of photography, especially where several lenses of varying foci are in constant use for a variety of purposes: — 246 A B C of Photography. Let ]) ~ Principal focus. F — Greater conjugate do. /'in Lesser do. do. -D zi: F + f — distance of image from object, rzz: Ratio of any dimension in original to the same dimension in copy (in case of reduction), or vice versa (in case of enlargement). a ~ Effective diameter of diaphragm. U. S. No. — 'Uniform System' No. of do. X — Comparative exposure required. _Ff_ F _ rf Then p = D X (r + 1)2 J) r + l r + l f -P ' + 1 {r + 1) _ p F _ 2) _ ^ r F-p r+l r D = p X + l)=p(^2 + r + __ F-p _ p F ^~ p "f-p"! U. S. No. = ^ 16 ~ 16 «2 16 ^2 ^2 N.B. — Eor ordinary landscape work, where r is greater than ^0, X may be taken as 16 ^2 Note.— In case the above may not be clear to some photograph- ers, the following rales may be better understood: — To find the principal focus of a lens (p), focus a near object in the camera, and measure the distance between it and the ground- glass (D) ; next find the proportion which any dimension in the ob- ject bears to the same dimension on the ground-glass (r). Thus, if the original dimension be four times as large as its reproduction, Synonyms of Chemicals. 247 we say that r equals (=) 4. Multiply Z) by r, and divide the pro- duct by the square of a number greater by one than r (r + 1)2. This rule was lately published by Mr. Debenham, To find the lesser conjugate focus (/") (if p and r are known) multiply p by the sum of r + 1 and divide the product by r. Or divide D by r+1. To find the greater conjugate focus (F) multiply p by r + 1. Or multiply f by r. To find B (the distance which the ground-glass should be from the object to be copied in order to get a given value for r) multiply p by the sum of r h2. To find r divide F—p (the difference between F and p) by p. Or divide p by f—p. Or divide F by f. To find X divide the square of f by 16 times the square of a (the diameter of aperture to lens). For example: focus an object which is five inches high, so that it is one inch high on the ground-glass; thus we know that r — 5. Next measure the distance between the object and the ground- glass (£)), which is found to be 45 inches. Ten p = 4:5 X (multipHed by 5 -^-(divided by) 0 X 6 = 6Vr. inches. f~ ^ 6 -^5 = 7V2 inches. Or f=A5~6 = 1% inches. F=6V4X 6 = 37V2 inches. Or F^Vj^ X 5 = 37^2 inches. D = 6\ X (5 + 2) = 6V^ X 7 V5 = 45 inches, r = (37V2 - 6VJ -f-6V* = 5. Or r = 6 V, -^-{7 V2 - 6^0 = 5. STOONYMS OF SOME OF THE IMPORTANT CHEMICALS USED IN PHOTOGRAPHY. r Acetic Acid. Alcohol Ammonium Carbonate, Chloride, Pyroligneous Acid Rectified Spirit, Spirits of Wine. Volatile Salt. Sal Ammoniac, Muriate or Hydro- Ammonium Sulphide. Benzole. Borax. Boric Acid. Calcium Carbonate. Carbolic Acid. Castile Soap. chlorate of Ammonia. Sulphuret of Ammonia. Benzine. Sodium Borate. Boracic Acid. Chalk. Phenol. Hard Soap. 248 A B C of Photogi^aphy. SYNONYMS OF SOME OF THE IMPORTANT CHEMICALS USED IN YV\0'm^^kYY^X.—(Contmued.) Copper Sulphate. Cyanine. Dextrine. Eau de Javelle. Ether. F'luoric Acid. Glucose. Gold, Chloride of Gold, Hyposulphite. Gum Dragon. Gun Cotton. Hydrochloric Acid. Hydrogen Peroxide. Hydroquinone. Iron, Perchlorite. „ Sulphate. Kaolin. Lac. Lead, Acetate of Lime, Chloride of. Magnesium Sulphate. Manganese, Binoxide. Mercuric Chloride. Mercury. Nitro-hydrochloric Acid. Platinum Perchloride. Potassium Bichromate. Carbonate. Cupric Sulphate, Blue Vitriol. Blue Copperas. Quinoline or Chinoline Blue. British Gum. Hypochlorite of Potash. Sulphuric Ether. Fluorhydric or Hydrofluoric Acid. Grape Sugar. Auric Chloride, Trichloride or Per* chloride of Gold. Sel d'Or. Tragacanth. Pyroxyline. Muriatic Acid, Spirit of Salts. Hydroxy!. Hydroquinone, Hydrochinone Quinol. Ferric Chloride. Ferrous Sulphate, Protosulphate of Iron. Green Copperas, Green Vitriol. China Clay. Shellac. Sugar of Lead, Goulard's powder. Chlorinated Lime, Bleaching powder. Epsom Salts. Black Oxide or Dioxide of Manganese. Per- or Bichloride of Mercury, Cor- rosive Sublimate. Quicksilver. Aqua-rejjia. Bichloride of Platinum. Platinum Chloride. Potassium Dichromate. Pearlash, Subcarbonate of Potash, Salt of Tartar, Salt of Wormwood. Equivalent Quantities of some Chlorides. 2 4g SYNONYMS OF SOME OY THE IMPORTANT CHEMICALS LSED IN PROTOGrRA?RY.—fCo7itinued.J Potassium Eerricyanide, „ Ferrocyanide. „ Nitrate. „ Oxalate. „ Sulphide. Pyrogallic Acid. Sodium Bicarbonate. Sodium Carbonate. „ Chloride. „ Hyposulphite. Tannic Acid. Uranium Nitrate. Zinc, Sulphate of Potash Ferridcyauide, Red prussiate of Potash. Yellow Prussiate of Potash. Nitre, Saltpetre Neutral Oxalate of Potash. Liver of Sulphur, Sulphurated Potash. Pyro, Pyrogallol. Sesqui-carbooate of Soda, Acid Carbonate of Soda. Hydi'osodic Carbonate. Washing Soda, Sal Soda, Soda Crystals, Carbonate of Soda. Salt, Sea Salt, Rock or Bay Salt. Hipo. Thiosulphate of Soda. Tannin. Uranyl Nitrate. White Vitriol. TABLE OF EQUIVALENT QUANTITIES OF SOME CHLOR- IDES USED IN PHOTOGRAPHY. Calculated for the Anhydrous and Dry Salts. By A. B. AuBEET, Professor of Chemistry, Maine State College, Orono, Me. t Equivalent Quantities of Various Bromides Used in Photography. Bromine. Ammonium Bromide. Potassium Bromide. Sodium Bromide. Cadmium Bromide -f- 4 Equi. Water. Zinc Bromide. 1 1-225 1-488 1-2^7 2-150 1-406 0-816 1 1-214 1 055 1-754 1-147 0-672 0-823 1 0-865 1-445 0 945 0-777 0-952 1-156 1 1-671 1-092 0-465 0-570 0-692 05-99 1 0-654 0-711 0-871 1-058 09-15 1-529 1 250 A B C of Photography EQUIVALENT QUANTITIES OF CHLORIDES.-(Co;?^'^>;7iP^/.) Sodium Potassium Ammonium Lithium Cadmium Chloride. Chloride. Chloride. Chloride. Chloride. 1 1-275 0-914 0-726 1-564 0'784 1 0-717 0-569 1 226 1-093 1394 1 0-794 1-710 1-376 1-75.5 1-285 1 2152 0-639 0-818 0-584 0-464 1 t Equivalent Quantities of Vaeious Iodides Used in Photography. Iodine. Ammoi inm Iodide, Potassium Iodide. Sodium Iodide. Cadmium . Iodide. Zinc Iodide. 1 ri42 1.307 1-181 1-441 1-255 0-876 1 1.145 1-035 1 262 1-099 0 765 0.874 1 0-903 1-102 0 960 0-847 0-967 1-107 1 1-220 1-063 0-694 0-793 0-907 0-820 1 0-871 0*797 0-910 1-042 0-941 1-148 1 t Equivalent Quantities of Yaeious Silver Salts Used in Photography. Silver(Metallic). Nitrate. Chloride. Bromide. Iodide. 1 1-574 1-328 1-741 2-176 0-6353 0-844 1-106 1-382 0-7523 1-184 1 1-310 1-638 0-5744 0-904 0.763 1 1 250 0"4595 0 723 0-610 1-800 1 t Equivalent Quantities of Various G-old Salts Used in Photography. Gold (Metallic) Chloride. Double Chloride of Gold and Potassium. Double Chloride of Gold and Sodiujji. 1 1-542 2-1048 2-0229 0-6485 1 1-3645 1-3119 0-4751 0-7326 1 0-9611 04943 0-7623 1-0405 1 t Translated and partly recalculated from the "Agenda du Chimiste." Solubilities of the Principal Substances, 251 TABLE OF THE SOLUBILITIES OF THE PRINCIPAL SUBSTANCES USED IN PHOTOGRAPHY. One part is soluable in — parts t - .2 of water. ^ 13 ^ 5-1 rv ^0) Solubility in Alcohol. M 0 5^ 0 S Cold. BoiliQg th ci c3 <^ Acii Boracic (Ad hydrous). 47 01 2 13 solubl e (Orvst ) 25-66 3*0 3-9 sol. in 6 parts @ 60° Citric 075 0'5 133*0 sol. in 1^15 pt. s.g. 820 lOO'O 3-0 10 soluble in 4 parts. Oxalic 15'5 1*0 6*47 in soluble Pvroof.illio 2-25 sol. in ale. and elher Salicylic 87-2 vry sol 0 35 easily soluble S uccinic 5*0 2-2 200 soluble in 3 parts very solubl e sol. in ale. and ether Tartaric •66 •5 150^0 soluble AiQiu (Potash.) 10-5 vry sol 9*52 insoluble (Annnonia) 7-32 13*66 A Tn TTi onlnTTi BromidG 14 0-78 411 sol. in 32*3 parts „ Carbonate . . . 3 3 •833 33*0 insoluble Chloride 2 7 1-00 37*02 spariiigly soluble Citrate deliqu escent vy. sol. less sol. in alcohol Iodide very solubl Q sol uble Nitrate 2*0 10 50*0 freely soluble Salicylate very solubl Q SucclQate S n Iphocyanide deliqu escent easily sol, in water and ale. Arium, Bromide . •96 104'2 easily soluble „ Chloride <^ ^^rystainsea 2-18 46^0 very slightly soluble " \ Anhydrous. 2-862 34*1 Iodide 0-48 6-35 208*3 easily soluble 12-2 2-84 8*18 easily solubl e easily soluble 0-71 067 „ Iodide 108 0^75 92-6 very soluble Calcium, Bromide (Cryst ) . 0-97 102-56 easily s luble „ Chloride 0-25 any qy 400-0 deliqu escent Cobalt, Chloride very solubl sol. in ale. and ether 252 A B C of Photography, TzVBT.E OF THE SOLUBILITIES OF THE PRINCIPAL SUBSTANCES USED IN YmnO^'^kYm..—(Contmued.) Copper, Bromide iCnpric) „ Chloride ,, „ Nitrate „ Sulphate Gold, Perchloride Iron, Chloride / Anhyd.. . . (Ferrous) \ Hydrated . „ Chloride (Ferric) „ Oxalate ,, „ Sulphate , „ ,, (Ferrous)... Lead, Actate ,, Nitrate Lithiam, Bromide Chloride „ Iodide Magnesiam, Bromide „ Chloride „ Iodide „ Sulphate . . . . . Mercuric, Chloride ) (Mercury) / Platinum, Bichloride Potassium, Bicnromate . . . Bromide Carbonate Chloride Citrate Cyanide Ferrocyanide . . Ferridcyanide. . Hydrate Iodide One part is soluable in — parts of water. Cold. Boiling deliqu solubl 2- 5 deliqu •2-0 0-6S very insolu solubl 3- 7 7-7 0- 66 1.315 0 61 deliqu 1-857 deliqu 1- 47 16'0 solubl lO'O 1*55 0-9 3 03 veiy deliqu 3*0 2- 54: 0-5 0.7 del. & ble, ex •30 3-45 escent escent 066 3-0 2-0 ^ Is r 03 c3 <1> vy. sol 40-0 vy. sol, 50-0 1470 Col. ept in *77'o 27-0 130 149-8 76-0 161*0 vy. sol, 53'8 vy. sol 6S.01: 6-25 io-0 64-5 111-0 33-0 solubl e escent 1.0 1-22 0-27 vy sol 33 3 39-37 200-0 1430 Solubility in Alcohol. sol. in ale. and ether very soluble insoluble soluble in ether sol. in 1 part alcohol easily soluble very soluble excess of oxalic acid soluble insoluble soluble in 12-5 parts soluble very soluble soluble slightly soluble soluble in 2*35 parts easily sol. in ale & ether slightly soluble insol. in pure alcohol Insoluble very sparingly soluble very soluble sol. in 40 pts. abs. ale. Solubilities of the Principal Substances. 253 TABLE OF THE SOLUBILITIES OF THE PRINCIPAL SUBSTANCES USED IN VV^O'X^O^^'^kVm.— (Continued.) One part is soluable in — parts of water. Cold. B linf ft. ; Solubility in Alcohol. Potassium, Nitrate Nitrite Oxalate(neutra]) oxalate (bin.) . , „ (quad.) . Permanganate . Sulphocyanide . Acetate Citrate Fluoride Nitrate Silver, Nitrite . , Oxalate „ Sulphate Sodium, Acetate (Cryst.).. „ Biborate (Borax) . , ., Bromide „ Carbonate (Cryst.). „ „ (Anhyd.). Chloride „ Citrate „ Hydrate „ Hyposulphite ..\ „ (Thiosulphate) / „ Iodide „ Nitrate „ Nitrite „ Phosphate „ Succinate Sulphate „ Sulphite 3 '5 deliqu 3- 0 400 20.17 16-0 very solubl deliqu I'O 300-0 " spar My sol. 2000 2>6 1244 113 2-0 3-85 2-77 1-0 1- 65 deliqu 0 55 1-136 deliqu 4- 0 very 2- 08 4-0 0-4 & solu slightl e in wa escent 0*5 dissol easily solubl 88 0 •66 2-0 1-0 2-07 2-77 escent 0-3 escent 2 0 oluble 0-41 28-57 ble 33.3 2 5 495 C-25 y sol. rm wate lOO'O 033 05 35 0 8-033 88 5 500 25-93 360 100-0 60-63 vy. sol. 180-0 88-03 vy. sol, 25-0 48-0 250 insoluble slightly soluble insoluble insoluble insoluble sol. in 4 pts. boiling ale. insoluble insoluble insoluble insoluble insoluble insoluble sparingly soluble sparingly soluble easily soluble insoluble sparingly soluble sol. in 37 parts ale. very soluble soluble slightly soluble 254 A jB C of Photography. TABLE OF THE SOLUBILITIES OF TFIE PRINCIPAL SUBSTANCES USED IN VRO'lOQ'^k^m.— (Continued.) One part is soluable in — parts of water. Cold. Boilin ^2 o o ^ Solubility in Alcohol. Sodium,Bisulphite „ Sulpbocyanide . . „ Tartrate „ Tungstate. Strontium, Bromide ,, Chloride „ Iodide Uranium, Bromide / (Hydrated) . . \ Nitrate „ Oxalate .... | Zinc, Bromide „ Chloride „ Iodide vesy s 1-75 40 101 1-88 0-56 deliqu 0-5 nearly insol. deliqu 0-333 vy. de oluble 2*0 0'27 & solu 30-0 escent liques. 56*37 25-0 99-0 53-0 178-5 ble 200*0 vy. sol 3000 & sol. insoluble insoluble sparingly soluble feebly soluble soluble sol. in ale. and ether insoluble very soluble very s >luble very soluble JW-5. ■ f/8 BEST AND SIMPLEST ANASTIGMATS. . jAYLOI^jAYljOI^^flop^Orl.,!!? Stoughton Street Works. LEICESTER, AND 18 Berners Street. LONDON, W. I I I jjijou Jjiographie^. 6d. Authoritatively Written, Well Printed, Substantially Bound (in Cloth), with Special Portraits. Price Sixpence Each. The volumes are, as the name of the series indicates, small. It is possible to carry them in the jacket pocket without the slightest inconvenience. They are, in printing, paper, and binding, equal in quality to any half-crown volume on the market. What the Press says the Bijous are:— "In an age when 'extracts,' 'essences,' and 'tabloids' are so much in favour, such highly-compressed literature will no doubt be popular." — Morning Post. "These little books are interesting," informative, and cleverly written. . . . deserve much more than a siiccess de cnriosite. . . . Got up very prettily, quite wonderfully so, in binding, paper, and type. A collection on a bookshelf would have a very attractive appearance." — Satnrday Review. "Concisely written, clearly printed, and give just the facts that busy people are anxious to know." — Lloyd's News. "They are compact in form, and full of information, tersely and lucidly given." — Sunday Stm. 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Lord Salisbury. By Edward Salmon. No. 6. Dr. W. G. Grace. By Acton Wye. No. 7. His Majesty King Edward Vllth. By Harry Whates. Double Volume. Price is. No. 8. Miss Marie CorelH. By Kent Carr. Double Volume. Price is. OTHERIS IN THE PRESS. London: Henry J. Drane, Salisbury Square, E.G. I I I SPECIJIJL to all who are interested in iiogFaphy whether amateurs or professionals. Write at once for our new list of Photographie - Publications — just issued. Handbooks on every branch of the Art of Photography, also Guide Books, Road Maps, and books for Autocarists and Electricians. ILIFFE & SONS, Ltd. 3, St. Bride Street, London, E.G. Natural Colour «^ F^hotog-raphy, (SANGER SHEPHERD PROCESS). A Simple, Inexiiensive and Reliable Process, based upon Sound Scientific Prin- ciples, for obtaining' Pliotog'raphs of any object in its Natural Colours, faitlifiilly re-producing' every Siiade and Tint, in a manner absolutely satisfying to tbe Eye. No complicated Viewing Instrument to get out of order, no special Lantern required as tlie Slides can be seen in the hand, either by Day or Artificial Liglit. There are no Lines or Dots to irritate the Eye. No expensive Viewing Screen required for each Slide. The Slides are perfectly transparent and brilliant pictures can be shown on a 10-ft. Screen with Limelight, or up to 20-ft. with the Electric Light. A number of examples are always on view at our Premises. Natural Colour Lantern Slides. Stereosco2'>ic Views and all Apparatus and Material for Worlcing the Process noiv ready, MEASURED LIGHT FILTERS for the THREE-COLOUR PROCESS. (Medal Royal Photograpliic Society, 1899.) SQUARE OF CIRCULAR, 1 TO 6 INCHES DIAMETER. sor.K 9iaki<:rs of thk Cadett Absolutus &. Gilvus Light Filters for the Spectrum Plate. Giving Piiotographs Avliicli represent the luminosity of all Colours exactly as seen by the Eye. All Sizes. Square or Circular. r .XT) vrv-TNGS STi. aED IN SEVERAL PATTERNS. r Gas, or Incandescent Electric Light, pectrum Plate, 1^/6, for Oil 13/6. DEVELOPER. Sample Tube, with Itamps. REENS for all Brands of Plates. TROSCOPES. licrograpliy. >7i Application. lERD & Co., F.KS OF ; Stands, Rotating Sectors, nent of Light & Colour, lation, &c. Ion St.; Holborn; London, W.C. to all who are interested in Photography whether amateurs or professionals. Write at once for our new list of Photographie - Publications — just issued. Handbooks on every branc the Art of Photography, also ( Books, Road Maps, and book. Autocarists and Electricians. ILIFFE & SONS, ] 3, St. Bride Street, London^ Natural Colour F^hotog-raphy, (SANGER SHEPHERD PROCESS). A Simple, Inexpensive and Reliable Process, based upon Sound Scientific Prin- ciples, for obtaining Photog'raphs of any object in Us Natural Colours, faithfully re-producing every Siuide and Tint, in a manner absolutely satisfying- to the Eye. No complicated Viewing Instrument to get out of order, no special Limtern required as the Slides can be seen in the hand, either by Day or Artificial Light. There are no Lines or Dots to irritate the Eye. No expensive Viewing Screen required for each Slide. The Slides are perfectly transparent and brilliant pictures can be shown on a lO-ft. Screen with Limelight, or up to 20-ft. with the Electric Light. A number of examples are always on view at our Premises. Natural Colour Lantern Slides, Stereoscopic Views and all Apimratiis and Material for Working the Process noio ready, MEASURED LIGHT FILTERS for the THREE-COLOUR PROCESS. (Medal Royal Photographic Society, 1899.) SQUARE OF CIRCULAR, 1 TO 6 INCHES DIAMETER. soi.K maki<:ks of thk Cadett Absolutus & Gilvus Light Filters for the Spectrum Plate. Giving Piiotograpiis Aviiich represent the luminosity of all Colours exactly as seen by the Eye. All Sizes. Sqxuire or Circular. CAPS AND FITTINGS STOCKED IN SEVERAL PATTERNS. See Circular. ROOM LANTERNS in Three Forms for Gas, or Incandescent Electric Light, tted witii 10 by 8 Safe Light for the Spectrum Plate, 12/6, for Oil 13/6. RUM PLATES stocked up to 15 by 12. SANGER SHEPHERD UNIVERSAL DEVELOPER. Sample Tube, with ;ooklet on Development, Post Free, 7 Stamps. )CHROMATIC LIGHT FILTERS or SCREENS for all Brands of Plates. LIAS for ail purposes. PHOTO SPECTROSCOPES. RAS and LIGHT FILTERS lor Photo Micrograpliy. Descriptive Circulars on Application. SANGER SHEPHERD & Co., ^lA^UFACTURF.KS OF mtific Apparatus, Cameras & Stands, Rotating Sectors, nstruments for the Measurement of Light & Colour, Speed Determination, &c. A.CTORY & OFFICES: & 7 Gray's Inn Passage, Red Lion St., Holborn, London, W.C. "No Better Food." Dr. ANDREW WILSON, F.R.S.E., &c PURE CONCENTRATED ^OCOCU 300 Gold Medals, &c. " The Most Perfect Form of Cocoa." QOYS HOSPITAL QAZETTE.