J, «. CR-Oi-lc«e(<_ 
 
 . i)oe5 
 
 ^7 
 
 ifyc.y- T,f.i 
 
C-onS, 
 
 Kh 
 
 4fc.8 
 
 I8^S 
 
 C<^S 
 
PRACTICAL HINTS 
 
 ON 
 
 THE DAGUERREOTYPE. 
 
 Notwithstanding the many valuable discoveries with which the 
 researches of Sir John Herschell, Mr. Fox Talbot, Mr. Robert Hunt, 
 and other distinguished philosophers, native and foreign, have 
 recently enriched the science of Photography, or, as it is now 
 termed, ^A.ctino-Chemistry,* the Daguerreotype process, first di- 
 vulged in 1839, still retains the highest place in public estimation. 
 The extreme heauty and delicacy of the pictures produced by this 
 method, and the comparative simplicity and certainty of the 
 operation, fully justify this preference, and account for the large 
 number of amateurs who are pursuing it in the present day, with 
 more or less success. While, however, the process is simple in 
 itself, it requires much care and nicety of manipulation, which is 
 only to be acquired by continued practice, or by the most careful 
 attention to the directions which are given by proficients in the 
 art, — and without which the operator is exposed to frequent annoy- 
 ance and disappointment. It is with the view of providing this 
 necessary assistance, that the following Hints have been thrown 
 together, in which all technicalities have been as much as pos- 
 sible avoided, and the directions made short and plain, so as to be 
 easily understood and followed. 
 
 The history of this invention is well known : Monsieur Daguerre 
 had for some time devoted his attention to the subject of Photo- 
 graphy, particularly to the means of fixing the images obtained in 
 the camera ohscura. While pursuing these enquiries in conjunction 
 with his partner, Mr, Niepc^e, he was led to adopt an entirely new j 
 
 • This term was suggested by Sir John Herschell, and adopted at a Meeting i 
 of the British Association, in September, 1844, to indicate that department of 
 Chemistry which is connected with 'the influence of the solar rays. 
 
 A2 
 
4 
 
 process, which, after many years of study and experiment, was 
 produced under the name of the Daguerreotype. The French 
 government appreciating the utility of invention, purchased it for 
 the benefit of all nations, granting to M, Daguerre a pension of 
 6,000 francs per annum for his life, and a proportional sum to M. 
 Isidore Niepc^e, the son of his former partner. Since the intro- 
 duction of the Daguerreotype, very many improvements have been 
 introduced, chiefly with a view to increase the sensibility of the 
 plates, on which the effect of light is now, with fine lenses, almost, 
 if not quite, instantaneous. 
 
 As the possession of a good apparatus is an essential attribute 
 of success in taking Daguerreotype pictures, it will be well to 
 begin by describing the various articles which are necessary or 
 convenient for this purpose. They are as follows : — 
 
 Camera Obscura. 
 
 The Camera Obscura, used/or taking DagueiTOtype Pictures (Fig, 
 1,) is a wooden box, furnished in front with a brass tube, in which 
 
 an achromatic lens is 
 made to slide. The 
 image is received on a 
 piece of ground glass 
 fi tted in a frame, which 
 slides in a groove in 
 the back of the came- 
 ra, and the focus is ad- 
 justed by a rack- work 
 in the brass tube of 
 the lens. The frame 
 and glass may be with- 
 drawn, and another 
 frame introduced, — 
 
 consisting of a wooden back, made to hold the silver plate, and a 
 sliding front which can be raised when the plate is to be submitted 
 to the action of the rays of light passing through the lens. This 
 Camera may be made of any dimensions, according to the diameter 
 of the lens employed. 
 
 WiLLATs’s Improved Photographic Camera, (Fig. 2,) 
 
 Is a great improvement on that just described. The lens. 
 
5 
 
 instead of sliding in a brass tube, is bedded in the front of the 
 
 Camera, by which 
 an increase of light 
 is obtained, the 
 quantity admitted 
 being regulated by 
 a diaphragm hav- 
 ing apertures of 
 different diameter. 
 The back part of 
 the camera slides 
 into the front and, 
 to secure a very ac- 
 curate adjustment 
 Fig. 2. is mounted with a 
 
 screw. It is moved in or out by turning a small handle at the back. 
 This camera is arranged with two grooves (a and 6), so as to allow 
 the'use of two lenses of different focal powers, according as por- 
 traits or views are desired. 
 
 The frame with the ground glass (Fig. 3) is furnished witli a 
 moveable top and sides, which when 
 extended, exclude the light, and 
 aid the operator in determining the 
 best focus. 
 
 
 
 
 
 1 > { i 
 i ! i 
 
 H li 
 
 
 
 
 i I ; 1 
 
 I i i j 
 
 i ! i i 
 
 
 
 
 Fig. 3. 
 
 The second frame, (Fig. 4) 
 consists of a box (6) made to 
 receive thin wooden frames 
 adapted to the various sized 
 daguerreotype plates, which 
 may be placed horizontally 
 or vertically, at pleasure : — 
 this frame is furnished with 
 a sliding door (c), laying over 
 the top of the camera when 
 raised. 
 
G 
 
 These cameras are usually made about 8 inches broad by 6^ high, 
 and will carry a 4 by 3-in. plate. The lenses of a very superior 
 quality are of If inch in diameter, and of 5 to 6 inches focus. 
 Double combination lenses may be added if desired. 
 
 The Double Camera Front, (Fig. 5,) 
 
 
 Fig. 5. 
 
 Contains the two lenses just alluded to, which 
 are moved by a rack-work adjustment (C), 
 and give a much sharper and brighter image 
 than can be obtained by the single lens. A 
 small reflecting mirror (E) is placed in front, 
 which reverses the objects in the camera, and 
 pourtrays them exactly as they appear in 
 nature. This combination is far more rapid 
 in its operation than the single lens. 
 
 Mercury Box. 
 
 This is a small box (Fig. 6) supported on two sliding legs, for 
 the sake of portability, having in the bottom an iron cup for hold- 
 ing the mercury, and in the inside a ledge to support the frame. 
 
7 
 
 and plate. In the front is introduced a piece of glass, protected 
 by a slide, to enable the operator to watch the developement of the 
 picture. A small thermometer is usually added, the bulb of which 
 dips into the iron trough, to enable the operator to observe the 
 temperature of the mercury. 
 
 Iodine and Bromine Troughs, (Fig. 7.) 
 
 These are either of glass or Berlin ware, encased in wood ; 
 
 they are furnished with 
 frames of various sizes 
 to hold the plates, and 
 with a cover of slate or 
 glass. They may be 
 used for any of the sen- 
 sitive solutions. 
 
 Polishing Block with Cover, (Fig. 8.) 
 
 This block is made of a 
 shape and size convenient 
 to the hand : — the plate ad- 
 heres firmly to the prepared 
 surface of the block, but 
 may be readily disengaged 
 when the process of polish- 
 ing is completed. 
 
 Fig. 8. 
 
 The Buff, (Fig. 9,) 
 
 Consists of a piece of wood of suitable dimensions, generally 
 
 about twelve inches by 
 \ three, covered with se- 
 
 1,' veral folds of white 
 
 cotton velvet, thorough- 
 ly cleansed from dirt, or 
 grease. 
 
 Fig 9. 
 
8 
 
 * 
 
 Plate Box, (Fig. 10.) 
 
 These boxes are of wood, or ja- 
 panned metal, fitted with grooves 
 which prevent the plates from touch- 
 ing each other -they are very 
 necessary to prevent the plates from 
 being scratched or rubbed. 
 
 Fixing Stand, (Fig. ii.) 
 
 This is a wire stand, made to support 
 the plate in an horizontal position, while 
 heat is applied in the fixing process : it is 
 also 'constructed with writing screws for 
 adjustment upon unequal surfaces. 
 
 The Washing Trough, (Fig. 12,) 
 
 Is of metal, or Berlin ware, accompanied by a stand of earthen- 
 ware, by which the frame 
 is supported in the proper 
 position while washing. An 
 apparatus has been con- 
 structed for performing this 
 operation with greater ease 
 and certainty; it is, how- 
 ever, little used. 
 
 Fig. 12. 
 
9 
 
 Claudet’s Frame and Improved Ditto. 
 
 Both these frames are used for carrying prepared plates. The 
 first is a thin metal frame, of the same dimensions as the plates it 
 is intended to carry, and is placed between them to keep them 
 from the light, and to prevent their touching each other, or gather- 
 ing dust. In this state they may be tied together, and carried in 
 the pocket without danger. The second is the same frame in a 
 metal case, which closes tightly, and still more effectually secures 
 them from light, dust, or contact. 
 
 The Tripod Staff, (Fig. 12,) 
 
 Upon which the camera may be rested, when no other suitable 
 place can be found, is a very necessary auxiliary in taking views ; 
 
 it is about 4 
 feet 6 inches 
 high, and car- 
 ries a small 
 table onwhich 
 the camera is 
 placed. 
 
 There are 
 several vari- 
 eties, differ- 
 ing in their 
 construction 
 Fig- 12 , and price. 
 
 The operator will also require a spirit lamp, with a large wick, 
 for heating the mercury, etc., etc. 
 
 Cotton Wool, which must be thoroughly clean, and free from 
 grease. 
 
 Prepared Tripoli, or Rotten Stone. 
 
 Prepared Lamp Black. 
 
 Olive Oil and Alcohol. 
 
 Chloride of Iodine. 
 
 One or other of the various sensitive solutions. 
 
 Distilled Mercury. 
 
 Hyposulphite of Soda. 
 
 Chloride of Gold, or Hyposulphite of Gold. 
 
 Frames of various sizes and patterns are made for mounting the 
 Daguerreotype Pictures with or without cases. 
 
10 
 
 DESCRIPTION OF THE PROCESS. 
 
 We shall now proceed to describe, briefly and clearly, the 
 Daguerreotype process, as practised by the most successful opera- 
 tors of the day, omitting such variations as are not essential to the 
 production of good proofs, and which tend rather to confuse than 
 instruct the amateur, but not knowingly discarding anything which 
 can facilitate his progress. And first, a remark or two on the silver 
 plates, upon which the picture is obtained. 
 
 These plates are made expressly for the Daguerreotype. There 
 are several sizes, the more useful of which are as follows : — 
 
 No. 1 2 by 2§ inches. 
 
 „ 2 .. „ 3 ^ „ 
 
 ,, 3 .. 3 4 ,, 
 
 „ 4 .. 4 „ 5 „ 
 
 The purchaser should be careful to select plates perfectly free 
 from any kind of blemish, which may be detected by breathing on 
 the plate, as a defect or spot, however small, will become a source 
 of great annoyance when a picture has been obtained, and much 
 time will have been needlessly consumed in polishing and pre- 
 paring them. 
 
 Cleaning and Polishing the Plates. 
 
 This operation must be performed with great care. Having 
 fixed the plate on the plate-holder, shake over it some finely 
 powdered tripoli, or rotten-stone, add a small quantity of pure- 
 alcohol, and with a piece of prepared cotton proceed to rub the 
 plate with a rapid circular motion, taking care not to press upon 
 it with much force : — the paste formed by the alcohol and tripoli, 
 must then be well cleaned off with fresh wool and dry tripoli, and 
 the above process repeated two or three times, until a clean surface 
 of pure silver is obtained. This is the best plan for a new plate : — 
 if the plate has been used before, and the picture has not been 
 what is termed fixed, the above operation will suflSce ; but if it 
 has been fixed, it is sometimes necessary to use a little olive oil 
 with the tripoli in the first instance, and then proceed with the 
 tripoli and alcohol as before. The plate is now ready for polishing, 
 which is best performed by rubbing the plate rapidly over the 
 buff, which must be kept well supplied with prepared lamp-black, 
 
11 
 
 pressing the plate hard and evenly against it, and changing the 
 direction frequently, but alw'ays ending by polishing in a direction 
 which will cross the picture you wish to obtain upon it ; that is, 
 if the plate is to be placed upright in the camera, finish it 
 from side to side, and vice versa. The last polish should be given 
 a short time before the plate is to be used ; and any dust which 
 may remain on it should be removed carefully, holding the plate 
 in an inverted position, wth a piece of cotton or a camel’s hair 
 pencil, just before the process of iodizing. 
 
 Iodizing the Plates. 
 
 The best way of securing an even co^ of iodine on the plate, is 
 to use the chloride of iodine, diluted with water, two or three 
 drops to an ounce, until it assumes the colour of pale sherry. A 
 little of this mixture being poured into the trough, (described p. 7) 
 sufficient to cover the bottom to about a quarter of an inch in 
 depth ; the plate must then be placed in the frame, and Carefully 
 put over this solution to expose it to its vapour : in about a minute 
 and a half, or two minutes, according to the temperature of the 
 atmosphere, the plate will be found, on inspection, to have acquired 
 a yellow tint, which will vary from a pale to a rich golden tint, 
 according to the time the plate is allowed to remain in contact with 
 the vapour. This degree of intensity must be varied, to suit the 
 quality of the accelerating liquid employed, as will presently be 
 explained ; but care must be taken that the tint on the plate does 
 not pass to the violet, or its sensitiveness will be diminished. The 
 colour of the plate may be inspected, by raising it and turning it 
 towards a white light, replacing it quickly on the trough. When 
 sufficiently iodized, it may be laid aside in the frame with its face 
 downwards, without injury. The same mixture may be used again 
 several times ; but it is better to renew it after each time of prepa- 
 ration. Iodine strewed at the bottom of the trough, and covered 
 with fine sand, may replace the chloride mixture, and will last much 
 longer, if carefully covered after use with an air-tight glass or 
 slate cover. 
 
 Accelerating Liquids. 
 
 There are many varieties of these known by the names of Eau 
 Brom^e, Bromide of Iodine, Redman’s Sensitive Solution, Hunga- 
 rian Liquid, etc., etc. The two latter are much used in England,, 
 
12 
 
 and will be found to answer well if properly applied. The liquid is 
 diluted with water in the proportion of about one dram to an ounce 
 and a half. A sufficient quantity having been poured into the 
 trough, the plate is placed over it, and allowed to remain until it 
 acquires a red colour, approaching in some cases to violet. The 
 following rules will guide the experimenter in using the different 
 liquids. If bromide of iodine be used as the accelerating agent, 
 the plate should remain over the iodine solution, until it is of a 
 deep yellow tint: and over the bromide, till of a deep rose colour. 
 If Redman’s solution, or the Hungarian liquid, a pale yellow and 
 light rose will be found to answer best. As a general rule : — if the 
 yellow colour produced by the iodine be pale, the red should be 
 pale also ; if deep, the red must incline to violet. When several 
 plates are to be prepared at the one time, the same solution will 
 serve for all ; but it seldom answers to preserve the mixtures for 
 any time ; and its use, after keeping, is one great cause of the 
 failures which so annoy amateurs. The bromine contained in these 
 solutions is very subtle, and escapes, leaving little else but iodine 
 remaining, which will, after some little time, give a red colour to 
 the plate, without rendering it sensitive, entirely disappointing 
 the expectations of the operator. The colour of the plate may be 
 examined as before, but care must be taken to replace the plate 
 over the solution for a few seconds, which removes the effect of the 
 light. When the liquid is renewed at each operation, one inspection, 
 at an interval determined by experience, will be generally sufficient. 
 From thirty to sixty seconds, according to temperature, are usually 
 required to produce the effect; in certain states of the atmos- 
 phere, a much longer time may be necessary. The plate is now 
 ready for the camera, and may be kept for twelve or eighteen hours, 
 if due care is taken to keep it secure from light or dust. Plates 
 prepared over night „are often considered more sensitive than those 
 prepared immediately before using. Frames to carry prepared 
 plates, may be purchased at the opticians. The prepared plate 
 must be transferred to the camera frame with extreme care neither 
 to expose it to light, or rub the surface. 
 
 Exposure in the Camera. 
 
 The form of camera most suitable for the purpose, has been 
 already described, page 5. The inside should be carefully dusted 
 before using. Having been placed opposite to the object to be 
 copied, and made perfectly steady, a clear and distinct representa- 
 
13 
 
 tion of the object must be obtained upon the ground glass, which 
 must then be withdrawn, and the frame containing the prepared 
 plate introduced in its place. The shutter may then be drawn up, 
 and the plate exposed to the light which passes through the lens. 
 The time of exposure must be decided by observation and experi- 
 ment ; as so much depends on the size and construction of the lens 
 or lenses, and the brightness or dulness of the season. With a good 
 achromatic lens, from five seconds to a minute and a half, will be 
 sufficient in almost every case. In another part will be found 
 some Directions for taking Portraits, Views, etc. which will assist 
 the beginner. The instant the assigned time has elapsed, the 
 shutter must be closed, and the frame may then be withdrawn in 
 readiness for the next operation. 
 
 Exposing the Plate to the Vapour of Mercury. 
 
 Into the cup at the bottom of the Mercury-box, put four or 
 five ounces of mercury, which must be pure, dry, and free from 
 moisture. It may be occasionally filtered by enclosing it in Chamois 
 leather, and gradually and carefully twisting the leather till the 
 mercury is forced through its pores clean and bright. The vapour 
 of the mercury is raised by the application of a spirit-lamp to the 
 cup which holds the mercury. When a thermometer is attached 
 to the mercury-box, a temperature of about 90 degrees will 
 raise the vapour of the mercury; if the box have no thermometer, 
 the cup may be heated until the mercury is pleasantly warm to the 
 finger. If the mercury cup is removed from the box in order to 
 its being heated, it is well after that operation to wipe the outside, 
 on which a slight steam from the spirit may have settled. The 
 plate, without having been removed from the slide, is then placed 
 over the mercury, where it must remain till the picture is perfectly 
 developed. Its progress may be obseved by the light of a candle 
 through the yellow glass in the front of the box. It generally takes 
 eight to fifteen minutes, or even longer, to perfect the operation ; 
 if, however, no outline is visible in about three minutes, either the 
 mercury has not been sufficiently heated, or the picture has been 
 removed too soon from the influence of light in the camera. If the 
 former be the case, the mercury may be again gently heated; but 
 if made too hot, the plate will become covered with small white 
 spots. The details are usually much better developed wlien the 
 picture has been brought out slowly, and with a moderate degree of 
 heat. 
 
14 
 
 Setting the Picture. 
 
 When the picture is sufficiently developed, it may either be set 
 &.t once, or carefully laid aside until a convenient opportunity 
 occurs. To set Daguerreotype pictures, they must be washed in a 
 suitable vessel, (a preserve pot large enough to contain the plate 
 will answer the purpose,) first in very pure water, and then in a 
 solution of hyposulphite of soda, about fifty grains to the ounce of 
 water, which must be carefully strained, and to which may be added 
 a small quantity of alcohol. The sensitive coating will soon be 
 removed, and the plate should again be washed in pure water, 
 agitating it perpendicularly, until the water runs off in a continuous 
 stream. 
 
 Fixing the Image. 
 
 The plate being taken from the water, which should never be 
 allowed to dry off, is placed upon a wire stand , adapted to preserve 
 it in a perfectly horizontal position. The gold solution, which may 
 be purchased of the opticians and chemists, or prepared according 
 to the formula given in the Appendix, is poured on the plate, 
 until it is entirely covered, and the flame of a large spirit lamp 
 applied to the under surface, in such a way that every part may be 
 equally heated. In a few moments, the picture will become very 
 clear and bright, when the lamp must be withdrawn, and the plate 
 removed quickly, and again plunged into cold water. The plate is 
 now finally washed, by pouring pure water at a boiling heat over it, 
 holding it as perpendicularly as possible. When the plate is quite 
 clean, it may be dried by blowing gently downwards, and when 
 neatly managed, it will be quite free from spots. The plate may be 
 supported on a stand, as in the washing apparatus. Fig. 12, page 8, 
 or held at the corner with a pair of pliars. The gold solution 
 must be rejected if it should have changed colour, or deposited any 
 precipitate. 
 
 The following new mode of fixing and strengthening pictures by 
 oxidation, has been proposed by Mr. Charles G. Page, m. d., 
 Professor of Chemistry, Columbia College, Washington : — 
 
 The impression being obtained upon a highly polished plate, and 
 made to receive, by galvanic agency, a very slight deposit of copper 
 from the cupreous cyanide of potassa, (the deposit of copper being 
 just enough to change the colour of the plate in the slightest degree,) 
 is washed very carefully with distilled water, and then heated over 
 a spirit lamp, until the light parts assume a pearly transparent 
 
15 
 
 appearance. The whitening and cleaning up of the picture by this 
 process, is far more beautiful than by the ordinary method of fixa- 
 tion by a deposit of gold. A small portrait fixed in this way, more 
 than a year since, remains unchanged, and continues to be the 
 admiration of persons interested in this art. One remarkable 
 effect produced by this mode of fixing, is the great hardening of 
 the surface, so that the impression is effaced with great difficulty. 
 
 I have kept a small portrait, thus treated, unsealed and uncovered 
 for over a year, and have frequently exposed it in various ways, and 
 rubbed it smartly with a tuft of cotton, without apparently injuring 
 it ; in fact, the oxidised surface is as little liable to change as the 
 surface of gold, and is much harder. 
 
 To succeed well in this process, the impression should be 
 carried as far as possible without solarization, the solution of the 
 hyposulphite of soda should be pure, and free from the traces of 
 sulphur, the plate should be carefully washed with distilled water, 
 both before and after it receives the deposit of copper, — in fact, the 
 whole experiment should be neatly performed, to prevent what the 
 French significantly call taches upon the plate, when the copper 
 comes to be oxidized. 
 
 The formula for the Daguerreotype process, which has now 
 been given, will, we trust, enable the amateur to pursue his 
 experiments with confidence and success. He will probably ex- 
 perience some disappointments, however carefully he may attend 
 to the rules which have been laid down, for there are few among 1 
 even the ablest experimenters who do not occasionally fail ; yet his ■ 
 perseverance will often be rewarded by an excellent picture, when | 
 perhaps, he least expects it. * 
 
 To obviate as much as possible these annoying failures, he should I 
 bear in mind the following Cautions, by which he may ofttimes • 
 discover the causes which prevent his success : — ] 
 
 Cautions. ij 
 
 1st. Never use the same accelerating liquid more than once or I 
 twice, and only at short intervals. It is better to throw it away ij 
 after preparing such plates as can be prepared at the same time. || 
 2nd. Be sure to replace the plate on the accelerating liquid tor jj 
 a moment or two after having observed the colour, and before j| 
 putting it in the camera. ji 
 
 3rd. Wipe the lens, and remove all dust and dampness from the | 
 
 camera before using. I 
 
 4th. Keep the camera and mercury box perfectly free from the | 
 
 vapour of iodine, bromine, etc. | 
 
16 
 
 6th. Filter the mercury through a piece of chamois leather, if it 
 should have film or dust collected upon it ; the hyposulphite solution 
 used to remove the colour of the plate in setting, must also be 
 filtered before using. 
 
 6th. Never use the gold solution after it has changed colour, or 
 thrown down a precipitate. This solution requires filtering oc- 
 casionally. 
 
 7th. Do not make the mercury too hot, it will spot the plate, and 
 spoil the picture. 
 
 8th. The direct rays of light must not enter the camera in 
 conjunction with those reflected from the object, the picture will 
 be veiled, and the colour of the plate changed to a thick green. 
 
 9th. If the picture appear clouded, it is probably either because 
 the plate has not been thoroughly cleaned, or has absorbed too 
 much Bromine; in the former case, the plate must be cleaned more 
 carefully, in the latter, the accelerating liquid must be changed, or 
 its strength reduced. If it be covered with a white film, the 
 plate has been exposed to light before putting into the camera, or 
 too much light has entered the camera, which may be remedied by 
 using a smaller diapragm. If the whites have become blue, it is 
 overdone, or the mercury has been too much heated ; if browned, 
 it is solarized. 
 
 COLORED DAGUERREOTYPES. 
 
 Daguerreotype portraits are now frequently met with beautifully 
 colored ; but the coloring is a process requiring great care and 
 judgment, and many good pictures are spoilt in fruitless experi- 
 ments. Several different methods of coloring have been proposed. 
 The simplest mode appears to be that of using dry colours ground 
 to a fine powder, and mixed with a little gum, also finely powdered. 
 These are laid on with a fine camel’s hair pencil, taking up very 
 little colour at a time, and will adhere to the plate by breathing 
 over it ; the picture must be well set. The best colours for this 
 purpose are carmine, rouge, chrome yellow, and ultramarine, by 
 combining which any tint may be obtained. 
 
 Mr. Claudet’s method is to dip a finely -pointed pencil in spirits 
 of wine, and taking a little of the colour, which must have been 
 pounded with spirits of wine, and again pulverized in a glass mortar, 
 — to apply it upon the plate. This coating must be slight, and may be 
 repeated if necessary ; but if too much is put on, it is difficult to 
 remove : the dry colour is applied on this coating, to which it will 
 be found to adhere. 
 
17 
 
 Mr. ChevalUer’s plan is to trace on the glass which is intended 
 to protect it, the outline of the picture, and then to tint it with 
 the colours used for painting the dissolving views, so as to corres- 
 pond with the picture underneath. When dry, the tracing may he 
 etfaced, the glass fixed, and the picture will then appeal’ through, 
 something in the style of a coloured lithograph. 
 
 M. Leotard de Senze covers the plate with a transparent mem- 
 brane, or vegetable paper, which he attaches by a solution of gum 
 or size, heated in a water bath ; on tliis membrane he applies 
 colours, mixed with spirits of wine and gum, or with white varnish 
 and alum.* 
 
 Mr. Page, whose new method of fixing the Daguerreotype proofs 
 is given page 15, has thrown out the following suggestions on the 
 subject of Coloring : — 
 
 As copper assumes various colours, according to the depth of 
 oxidation upon its surface, it follows, that if a thicker coating than 
 the first mentioned can be put upon the plate, without impairing 
 the impression, various colours may be obtained during the fixation. 
 
 It is impossible for me to give any definite rules concerning this 
 last process ; but I will state, in a general way, that my best results 
 were obtained by giving the plate such a coating of copper as to 
 change the tone of the picture, that is, give it a coppery colour, and ^ 
 then heating it over a spirit lamp until it assumes the colour desired. 
 
 I have now an exposed picture treated in this way at the same time 
 with the two above mentioned, and it remains unchanged, it is of 
 a beautiful green colour, and the impression has not suffered in the 
 least by the oxidation. Should this process be perfected, so as to 
 render it generally available, it will be greatly superior to the 
 present inartistical mode of stippling dry colours upon the impres- 
 sion ; for the colour here is due to the surface of the picture itself. 
 
 For pure landscapes, it has a pleasing effect, and by adopting some 
 of the recent inventions for stopping out the deposit of copper, the 
 green colour may be had wherever desired. In some pictures, a 
 curious variety of colours is obtained, owing to the varying thick- 
 ness of the deposit of copper, which is governed by the thickness | 
 of the deposit of mercury forming the picture. In one instance, 
 a clear and beautiful ruby colour was produced, limited, in a well- 
 defined manner, to the drapery, while all other parts were green. 
 
 • These three receipts are condensed from M. Lerebour’s excellent Traite de 
 Photographie, from which other valuable suggestions are taken. 
 
 B 
 
18 
 
 PORTRAITS, VIEWS, ETC. 
 
 The following hints, gathered from various sources, will be useful 
 to those who have not seen the operation performed by experienced 
 practitioners ; — 
 
 Portraits. — The sitter should be placed in an easy natural 
 position, in a chair which has a support or rest for the head ; an 
 iron rod, with a ring at the end, affixed to the back of the cltair, 
 which can be raised or lowered at pleasure, answers well. Portraits 
 are taken with great rapidity in the open air : from five to twenty 
 seconds being usually sufficient, with a good lens, and a clear sky. 
 The direct rays of the sun must be carefully avoided, and it is often 
 desirable to place the sitter under a kind of canopy, or roof of 
 stuff, or glass, which should be blue, that color intercepting fewer 
 of the chemical rays than any other. One side of the model should 
 be rather more illuminated than the other ; indeed the position, 
 attitude, arrangement of the dress, etc., all require attention, with 
 a view to artistical effect. If the portrait is taken in a room, the 
 sitter should be placed in front of a door or window, through which 
 there is a strong and uninterrupted light ; the time of sitting must 
 of course be extended : a minute to a minute-and-a-half will 
 generally be required. The perfect illumination of the model may 
 be assisted by mirrors, or white linen cloths arranged so as to reflect 
 the light when it is most needed. A short focus lens is best for 
 portraits, as it operates more quickly, but care must be taken to 
 keep the whole of that part of the person appearing in the plate 
 as much in the same plane as possible, otherwise any projecting part,^ 
 as a hand or leg, will be represented greatly out of proportion. The 
 position of the camera must be determined by circumstances; 
 generally, it should be placed nearly on a level with the face, as the 
 most important point of view. With respect to back grounds, 
 some persons use painted scenes, representing terraces, balconies, 
 gardens, etc. ; but they are seldom so correctly managed as to appear 
 well in focus, and certainly rather take off the attention from the 
 main figure. A back ground of an even colour is preferred by 
 many, and may be dark or light according to taste, and the dress 
 or complexion of the model. In the former case, a drab or slate 
 colour suits well ; in the latter, an old blanket answers better than 
 any thing else. A table with books, vases of flowers, etc. may be 
 arranged by the side of the sitter, if care be taken that they come 
 
Id 
 
 nicely in the focus. Too much white in the dress should carefully 
 be avoided. 
 
 Views. — The points from which buildings or views can be taken 
 with the best advantage, vary so greatly, that the operator must be 
 left pretty much to his own discretion, in choosing a position. As 
 a general rule in taking a building, monuments, etc., it is advisable 
 to place the camera at a distance of about twice its greatest dimen- 
 sions, and, if practicable, at about one-third its height. If the 
 whole of the building or buildings be not in the same plane, select 
 the most important portion to be most clearly defined, or take 
 several views, in each of which certain points are brought out more 
 distinctly. If an old and new building are to be introduced in the 
 same picture, which should, if possible, be avoided, a black screen 
 or handkerchief, or some other opaque body, should be placed over 
 the lens for a moment or two, so as to cut off the rays of light 
 reflected from the brighter portions of the object, the position of 
 which may be previously observed on the ground glass. The same 
 precaution should be taken when the sky is very blue, or strongly 
 illuminated by the sun. The best time for taking views, is un- 
 doubtedly the earlier part of the day, though good pictures are 
 often taken in the afternoon. The time required to obtain a good 
 impression, varies so much according to the lens, the weather, the 
 hour, etc., that no certain rules can be given on the subject, — 
 experience will prove the best guide. 
 
 Engravings, Drawings, etc. may be copied very beautifully 
 with a little care ; the whole of the model being in the same 
 plane, there is little difficulty in producing a good effect. The 
 object to be copied must be placed in a good light, taking care to 
 have every part equally illuminated. To secure sharpness, the 
 model is placed in the open daylight, in which case a proof may 
 generally be procured in about fifteen seconds ; in the full sun- 
 shine, the impression is made almost instantaneously. 
 
 Machinery, Statuary, and Articles of Vertu, require to 
 be arranged in suitable positions, so that the light may fall upon 
 the object most effectively. The light may be reflected from 
 mirrors, white linen, etc. etc. 
 
 B 2 
 
20 
 
 ENGRAVING DAGUERREOTYPE PLATES. 
 
 Several plans have been suggested for accomplishing this much 
 (lesired object ; none, however, seem so well adapted as the follow- 
 ing, recently patented by M. Claudet, to whom the art is already 
 much indebted. In the specification, the process is explained as 
 follows : — • 
 
 The process is established upon the following facts, which have 
 come to the knowledge of the inventor: — 
 
 1. A mixed acid, composed of water, nitric acid, nitrate of pot- 
 assa, and common salt, in certain proportions, being poured upon a 
 Daguerrotype picture attacks the pure silver, forming a chloride of 
 that metal, and does not affect the white parts, which are produced 
 by the mercury ; but this action does not continue long. Then, by 
 a treatment with ammonia (ammonia containing already chloride of 
 silver in solution is preferable for this operation), the chloride of 
 silver is dissolved, and washed off, and the metal being again in its 
 naked state, or cleansed from the chloride, it can be attacked afresh 
 by the same acid. This acid acts better warm than cold. 
 
 2 As all metallic surfaces are soon covered, when exposed to the 
 atmosphere, with greasy or resinous matters, it is necessary, in order 
 that the action of the acid upon the pure silver should have its full 
 effect, for the surface to be perfectly purified ; this is effected by 
 the employment of alcohol and caustic potash. 
 
 3. When a Daguerrotype picture is submitted to the effect of a 
 boiling concentrated solution of caustic potash, before being attacked 
 by the acid, the state of its surface is so modified that the acid 
 spares or leaves, in the parts which it attacks, a great number of 
 points, which form the grain of the engraving. 
 
 4. When the effect of the acid is not sufficient, or in other words, 
 if it has not bitten deep enough, the effect is increased by the fol- 
 lowing process : — Ink the plate as copper-plate printers do, but 
 with a siccative ink ; when the ink is sufficiently dry, polish the 
 white parts of the plate, and gild it by the electrotype process ; 
 then wash it with warm caustic potash, and bite in with an acid, 
 which will not attack the gold, but only the metal in those parts 
 which, having been protected by the ink, have not received the 
 coating of gold. By these means the engraving is completed, as 
 by the action of the acid alone it is not generally bitten in deep 
 enough. 
 
21 
 
 5. To protect the plate from the effects of wear, produced by 
 the operation of pi loting, the following process is employed : — The 
 surface of the plate is covered with a very thin coating of copper, 
 by means of the electrotype piocess, before submitting it to the 
 operation of printing; and when that pellicle or coating of copper 
 begins to show signs of wear, it must be removed altogether, by 
 plunging the plate in ammonia, or in a weak acid which, by electro 
 chemical action, will dissolve the copper, without affecting th.e 
 metal under it ; the plate is then coppered again, by the same 
 mean'', and is then ready for producing a further number of im- 
 pressions. This re-coating operation may be repeated as many 
 times as may be required. The following is the descri|)tion of the 
 whole process, which is divided into two parts, consisting of a pre- 
 paratory and finishing process : — 
 
 Preparatory Engraving . — For this operation, which is the most 
 delicate, it is necessary to have, 1 . A saturated solution of caustic 
 potash. 2. Pure nitric acid at 36® of the areometer of Beaiim6 
 (spec. grav. P333.) 3. A solution of nitrite of potassa, composed 
 
 of 100 parts of water and 5 parts of nitrite, by weight. 4. A solu- 
 tion of common salt, composed of water 100 parts, and salt 10 
 parts, by weight. 5. A weak solution of ammoniacal chloride of 
 silver, with an excess of ammonia. The ammoniacal chloride of 
 silver must be diluted with 15 or 20 parts of pure water. In the 
 description of the process, this solution will be called ammoniacal 
 chloride of silver. 6. A weak solution of ammonia, containing 4 or 
 5 thousandths of liquid ammonia. This solution will be called 
 ammoniacal water. 7. A weak solution of caustic potash, contain- 
 ing 4 or 5 thousandths of the saturated solution, which will be 
 called alkaline water. 8. A solution composed of water 4 parts, 
 saturated solution of potash 2 parts, alcohol 1 part, all in volume. 
 This solution will be called alcoholized potash. 9. Acidulated water, 
 composed of water 100 parts, and nitric acid 2 parts, in volume. 
 Besides, it is necessary to have three capsulas or dishes, made of 
 porcelain, large enough to contain the plate, and covered with an 
 air-tight piece of ground plate-glass, and two or three more capsulae 
 which do not require to be covered ; two or three glass funnels, to 
 wash the plate; and two or three glass holders, in the shape of a 
 spoon or shovel, by which the plate is supported when put in and 
 taken out of the solution, without touching it with the fingers. 
 
 The Daguerrotype plate is submitted to the engraving process, 
 alter having been washed in the hyposulphite of soda, and after- 
 wards in distilled water. 
 
22 
 
 I First process for biting in or engraving the plate. — The following 
 ! solutions must be put in the capsiilaB, in sufficient quantity, so as to 
 j entirely cover the plate: — I. Acidulated water. ^2. Alkaline water. 
 3. Alcoholized potash, in covered capsulae. 4. Caustic potash, in 
 , covered capsulae. 5. Distilled water. 
 
 The plate being put upon the glass holder or spoon, is plunged 
 in the acidulated water, and agitated during a few seconds, then 
 [ put into a glass funnel, and washed with distilled water. It is 
 
 I taken again with the glass spoon, and plunged in the capsiila con- 
 taining alcoholized potash. This capsula is covered with its glass 
 cover, and then heated, by means of a spirit-lamp, to about 144® 
 Fahrenheit, The plate must remain in the capsula half an hour, 
 during which the solution is heated now and then, and agitated. 
 
 j During that time, the following acid solution, which will be called 
 I normal acid, must be prepared ; it is composed as follows : — Water 
 { 600 parts, nitric acid 45 parts, solution of nitrite of potassa 12 parts, 
 
 II solution of common salt 45 parts. These proportions are in volume. 
 ?|The normal acid must be poured in a capsula, covered with its glass 
 
 cover, and a sufficient quantity must be kept in the bottle, 
 ii When the plate has been immersed in the alcoholized potash 
 11 during half an hour, it is taken out of the solution by means of the 
 I; glass holder, and immediately plunged in the alkaline water, and 
 !i agitated pretty strongly ; from thence it is put in distilled water. (A) 
 
 ' This being done, the plate is plunged in the acidulated water, and 
 
 I moved about therein for a few seconds: it is then put into the 
 ; normal acid. When the plate has been immersed a few seconds in 
 
 the acid, it is taken out by means of the glass holder, taking care to 
 Ij keep it as much as possible covered with the solution, and it is im- 
 i mediately placed horizontally upon a stand, and as much acid as the 
 t' plate can hold is poured upon it from the bottle ; it is then heated 
 
 I I with a spirit-lamp, but without attaining the boiling point. During 
 I this operation it is better to stir or move about the acid on the plate 
 
 by pumping it, and ejecting it again, by means of a pipette or glass 
 i syringe; after two or three minutes the acid is thrown away, the 
 ji plate is put in the glass funnel, and there well washed with water, 
 
 ! and afterwards with distilled water. (B) 
 
 I Then, without letting the plate dry, it is put upon the fingers of 
 I the left hand, and with the right hand some ammoniacal chloride of 
 |i silver, which is moved about the surface by balancing the hand, is 
 ; poured upon it ; the solution is renewed until the chloride, formed 
 |i by the action of the acid, is dissolved ; the plate is then washed by 
 
 i pouring upon it a large quantity of ammoniacal water, and after- 
 
 ii wards some distilled water. (C) 
 
23 
 
 Without allowing the plate to dry, it is then put in the caustic 
 potash, and the capsula being placed upon the stand, the potash is 
 heated up to the boiling point ; it is then left to cool (D) ; and be- 
 ginning again the operations described from A to D, a second biting 
 is obtained ; i^d by repeating again the operations described in A 
 and B, a third biting is produced. The plate is then dried ; in this 
 state the black parts of the plate are filled with chloride of silver. 
 
 The plate is then polished until the white parts are perfectly pure 
 and bright. This polishing is done with cotton and “ ponce’^ 
 (pumice stone) ; afterwards, the chloride of silver, filling the black 
 parts, is cleansed by the means described in B and C. The plate is 
 then dried ; but before drying, it is well to rub the plate slightly 
 with the finger, in order to take off from the black parts any 
 remains of an insoluble body which generally remain on it. The 
 preparatory engraving is then finished, and the plate has the 
 appearance of a very delicate aquatint engraved plate, not very 
 deeply b.tten in. 
 
 Nevertheless, if the operation has been well managed, and has 
 been successful, it is deep enough to allow the printing of a con- 
 siderable number of copies. 
 
 Note. — Sometimes, instead of treating the plate with the boiling 
 potash in the capsula, a similar result may be obtained by placing 
 the plate upon the stand, covering it with the solution, and heating 
 it by means of a spirit-lamp, until, by evaporation, the potash be- 
 comes in a state of ignited fusion. By this means the grain is finer, 
 but the white parts are more liable to be attacked. 
 
 Last operation of biting in . — This operation requires some of the 
 re-agents before named, and also, 
 
 1. A siccative ink, made of linseed oil, rendered very siccative by 
 boiling it sufficiently with litharge ; it may be thickened with 
 calcined lamp-black. 
 
 2. An electrotype apparatus, and some solutions fit to gild and 
 copper the plate. 
 
 Means of operating . — The plate must be inked as copper-plate 
 printers do, taking care to clean off the white parts more perfectly 
 than usual ; the plate is then to be placed in a room sufficiently 
 warm, until the ink is well dried, which requires more or less time, 
 according to the nature of the oil employed. The drying of the 
 oil may be hastened by heating the plate upon the stand with the 
 lamp, but the slow process is more perfect and certain. 
 
24 
 
 W hen the ink is well dried, the white parts are cleaned again by 
 polishing the plate with cotton and pounce, or any other polishing 
 powder : a ball of cottoti, or any other matter, covered with a thin 
 piece of caoutchouc or skin, can be used for this purpose. When 
 polished, the plate is ready to receive the electro* chemical-coating 
 of gold, which will protect the white parts. 
 
 Gildhig . — I'he gilding is obtained by any of the various processes 
 of electrotyping which are known. The only indispensable condi- 
 tion is, that the surface obtained by the precipitation must not be 
 liable to be attacked by any weak acid ; a solution answering this 
 purpose is made of ten parts (by weight) of ferrocyanide of potas- 
 sium, one part of chloride of gold, and 1000 parts of water, used 
 with a galvanic battery. During the gilding the plate must be 
 turned in several positions, in order to regulate the metallic deposit. 
 In some cases the gilding may be made more perfect, if the plate is 
 covered with a thin coating of mercury before being put in the 
 gilding solution. 
 
 When the plate is gilded, it must be treated with the boiling 
 caustic potash, by the process already indicated for the preparatory 
 engraving, in order to cleanse it from all the dried oil or ink which 
 fills the hollows. The plate is then washed and dried, and when the 
 oil employed has been thickened with the lamp-black, the surface 
 of the plate is rubbed with crumb of bread, in order to cleanse and 
 take off the black remaining ; then, the white parts being covered 
 and protected by a varnish not liable to be attacked, and the black 
 parts being uncovered and clean, the plate can be bitten in by aqua- 
 fortis, according to the ordinary process used by engravers. 
 
 This operation must be done upon the stand, and not by immers- 
 ing the plate in the solution. 
 
 Before this last biting-in, if the preparatory engraving has not 
 succeeded well, and the plate still wants a sufficient grain, it can be 
 given by the various processes of aquatint engraving. 
 
 Before submitting the plate to the operation of printing, in order 
 to insure an unlimited number of copies, it is necessary, as before 
 stated, to protect it by a slight coating of copper, which is obtained 
 by the electrotype process ; otherwise the printing would soon wear 
 the plate. This coating must be kept very thin, lest the fineness of 
 the engraving, and the polish of the white parts, should be de- 
 stroyed. In this state the plate can be delivered to the printer. 
 
 After a certain number of impressions have been obtained, it will 
 be perceived that the coating of copper is worn in some places ; 
 
25 
 
 then, this coating must be removed, and a fresh one applied in its 
 place. For this purpose, the plate must be purified and cleansed 
 by warm potash, and plunged in a weak acid composed as follows : — 
 Water, 600 parts; nitric acid, 50 parts; nitrous acid of engravers, 
 
 5 parts ; all in volume. Tiiis acid will dissolve the coating of 
 copper, and the plate being coppered again by the same means as 
 before, may be again submitted to the operation of printing ; and as 
 nothing can prevent the success of a repetition of the same opera- 
 tion, any number of impressions may be obtained. The coating of i 
 copper can also be removed by caustic ammonia. ! 
 
 The Daguerrotype plate engraved by this process, which consti- 
 tute the present invention, consist, — 
 
 First, — in the discovery and employment of certain properties 
 of a mixture composed of nitric acid, nitrous acid, and hydrochloric 
 acid, in determined or fixed proportions. The two last-mentioned 
 acids may be employed either in a free state, or combined with 
 alkaline or other basis. This mixed acid has the property of biting 
 the pure silver which forms the black parts of the Daguerrotype 
 picture, without attacking the white parts formed by the amalgam | 
 of mercury. The result of the action of the biting is to form on the | 
 black parts of the picture an insoluble chloride of silver ; and this \ 
 chloride of silver which when formed stops the action of the acid, • 
 is dissolved by ammonia, which allows the biting to continue. i 
 
 Secondly, — in the discovery of certain properties of a warm 
 solution of caustic potash, and in the employment of the said solu- I 
 tion, by which the mercury forming the picture is better and deeper i 
 amalgamated with the silver under it, so that many imperceptible | 
 points of the amalgam are effected in such a manner that the acid | 
 has no action upon them. | 
 
 Thirdly, — in the discovery and employment of a process which 
 produces a grain favourable to the engraving, by which the biting jl 
 on the plate is rendered deeper. This is effected by filling the parts ji 
 engraved with a siccative ink, or any other substance, and then ■' 
 gilding the plate by the electrotype process; the gold is not de- j 
 posited on the parts protected by the ink. When the plate is gilded, [ 
 the ink is cleansed by the caustic potash, and the plate may be sub- [| 
 mitted to the effects of an acid which does not attack the coating of j] 
 gold, but bites only on the silver in the parts already engraved by j 
 the first operation. • 
 
 Fourthly, — in the employment of a process by which the plate is f; 
 protected from the wear of the printing operation. This is effected 
 by covering the plate before printing with a shght coating of copper G 
 
26 
 
 by the electrotype process, and when the coating begins to wear by 
 printing, it is removed by a weak acid, or by ammonia, which dis- 
 solves the copper without affecting the silver under it. The plate 
 is coppered again, and after another printing, the same operation is 
 repeated, so that a considerable number of copies may be printed 
 without much injury to the engraving. 
 
 M. Daguerre’s New Mode of Preparing Plates. 
 
 The subjoined account of this process is taken from a letter of 
 M. Daguerre’s to Mr. Arago, of the Academic, published in the 
 Comtes Rendus, No. 17, April 2-2nd, 1844. It presents many diffi- 
 culties, and has been adopted by very few persons in this country, 
 / but as the latest contribution of the inventor of the Daguerreotype, 
 it deserves at least a fair trial. 
 
 After stating that the proofs now obtained, though not deficient 
 in purity, leave much to be descried, in general effect and relief. 
 Monsieur Daguerre continues thus : — 
 
 It is by superposing on the plate several metals, reducing;! them 
 to powder by friction, and by acidulating the empty spaces which 
 the molecules leave, that I have been enabled to develop ’galvanic 
 actions which permit the employment of a much thickei\layer of 
 iodide, without having to fear, during the operation of light in the 
 camera-obscura, the influence of the liberated iodine. 
 
 The new combination which I employ, and which is composed 
 of several metallic oxides, has the advantage of giving a sensible 
 layer capable of receiving impressions simultaneously by all the 
 degrees of tone ; and I thus obtain, in a very short space of time, 
 the representation of objects vividly enlightened with demi-tints, 
 all of which retain, as in nature, their transparency and their 
 relative value. 
 
 By adding gold to the metals which I first used, I am enabled 
 to avoid the great difficulty which the use of bromine, as an 
 accelerating substance, presented. It is known, that only very 
 experienced persons could employ bromine with success, and that 
 they were able to obtain the maximum of sensibility only by 
 .chance, since it is impossible to determine this point very precisely, 
 and since immediately beyond it the bromine attacks the silver, 
 and is opposed to the formation of the image. 
 
 W ith my new means, the layer of iodine is always saturated 
 with bromine, since the plate may, without inconvenience, be left 
 
27 
 
 exposed to the vapour of this substance for at least half the neces- 
 sary time; for the application of the layer of gold is op[)osed to 
 the formation of what is called the veil of bromine. This facility 
 must not, however, be abused ; for the layer of gold, being very thin, 
 might be attacked, especially if too much polished. The process 
 which I am about to give may, perhaps, be found rather com- 
 plicated ; but, notwithstanding my desire to simplify it as much as 
 possible, I have been led, on the contrary, by the results of my 
 experiment, to multiply the substances employed, all of which play 
 an important part in the whole process. I regard them all as 
 necessary for obtaining a complete result, which must be the case, 
 since I have only gradually arrived at discovering the properties of 
 these different metals, one of which aids in promptitude, the other 
 in the vigour of the impression, etc. 
 
 From the concurrence of these substances, arises a power which 
 neutralises all the unknown effects which so often oppose the 
 formation of the image. 
 
 I think, besides, that science and art should not be interrupted bj' 
 the consideration of a more or less long manipulation ; we should be 
 contented to obtain beautiful results at this price, especially when 
 the means of execution are easy. 
 
 For the galvanic preparation of the plate does not present any 
 difficulty. The operation is divided into two principal parts : the 
 first, which is the longest, may be made a long time previously, 
 and may be regarded as the completion of the manufacture of the 
 plate. This operation, being once made, serves indefinitely ; and, 
 without recommencing it, a great number of impressions may 
 be made on the same plate. 
 
 Preparation of the New Substances. 
 
 Aqueous Solution of Bichloride of Mercury . — 5 decigrammes of 
 bichloride of mercury in 700 grammes of distilled water. 
 
 Solution of Cyanide of Mercury . — A flask of distilled water is 
 saturated with cyanide of mercury, and a certain quantity is 
 decanted, which is diluted by an equal quantity of distilled water. 
 
 Acidulated White Oil of Petroleum . — This oil is acidulated by 
 mixing with it one-tenth of pure nitric acid, leaving it at least 
 forty-eight hours, occasionally agitating the flask. The oil, which 
 is acidulated, and which then powerfully reddens litmus paper, is 
 decanted. It is also a little coloured, but remains very limpid. 
 
 Solution of Chloride of Gold and Platinum . — In order not toj 
 
28 
 
 multiply the solutions, I take the ordinary chloride of gold, used 
 for fixing the impressions, and which is composed of I gramme of 
 chloride of gold, and 4 grammes of hyphosulphite of soda, to a 
 quart of distilled water. 
 
 With respect to chloride of platinum, 2§ decigrammes must be 
 dissolved in three quarts of distilled water; these two solutions 
 are mixed in equal quantities. 
 
 Modus Operandi, 
 
 First Preparation of the Plate. 
 
 Note , — For the sake of brevity in the following description, I 
 will abridge the name of each substance. Thus, I will say, to 
 designate the aqueous solution of bichloride of mercury, sublimate ; 
 for the solution of cyanide of mercury, cyanide ; for the acidulated 
 oil of petroleum, oil ; for the solution of chloride of gold and 
 platinum, gold and platinum ; and for the oxide of iron, rouge 
 only. 
 
 The plate is first polished with sublimate and tripoli, and after- 
 wards with rouge, until a beautiful black is arrived at. Then, the 
 plate is layed on the horizontal plate, and the solution of cyanide is 
 poured on it and heated over a lamp, as in fixing an impression 
 with chloride of gold. The mercury is deposited, and forms a 
 whitish layer. The plate is allowed to cool a little, and, after 
 having poured off the liquid, it is dried by rubbing with cotton 
 and sprinkling it with rouge. 
 
 It is now necessary to polish the whitish layer deposited by the 
 mercury. With a piece of cotton steeped in oil and rouge, this 
 layer is rubbed until it becomes of a fine black. In the last place, 
 it may be rubbed very strongly, but with cotton alone, in order to 
 render the acidulated layer as thin as possible. 
 
 The plate is afterwards placed on the horizontal plane, and the 
 solution of gold and platinum is poured bn. It is heated in the 
 ordinary manner; it is then allowed to cool, the liquid is poured off, 
 and it is dried by gentle friction with cotton and rouge. 
 
 This operation must be performed with care, especially when 
 the impression is not immediately continued ; for, otherwise, some 
 lines of liquid would be left on the plate, which it is difficult to 
 get rid of. After this last friction, the plates should be only dried, 
 and not polished. 
 
 This concludes the first preparation of the plate, which may be 
 made a long time previously. 
 
29 
 
 Second Preparation. 
 
 Note . — I do not think it fit to allow a longer interval than twelve 
 hours to intervene between this operation and iodizing the plate. 
 
 We left the plate with a deposit of gold and platinum. In 
 order to polish the metallic layer, the plate is rubbed with a piece 
 of cotton, and oil and rouge, until it again becomes black ; and then 
 with alcohol and cotton only, in order to remove this layer of 
 rouge as much as possible. 
 
 The plate is then rubbed very strongly, and passing several 
 times over the same places, with cotton impregnated with cyanide. 
 
 As this layer dries very promptly, it might leave on the plate 
 traces cf inequality ; in order to avoid this, the cyanide must be 
 again passed over it, and, while the plate is still moist, we quickly 
 rub over the whole surface of the plate with cotton imbibed with a j 
 little oil, thus mixing these two substances ; then, with a piece of 
 dry cotton, we rub in order to unite, and at the same time, to dry 
 the plate, taking care to remove from the cotton the parts which 
 are moistened with cyanide and oil. Finally, as the cottdn still 
 leaves traces, the plate is likewise sprinkled with a little rouge, 
 which is removed by gently rubbing. 
 
 Afterwards, the plate is again rubbed with cotton impregnated ! 
 with oil, only in such a manner as to make the burnish of the metal \ 
 return ; it is then sprinkled with rouge, and then very gently ij 
 rubbed round, in such a., manner as to remove all the rouge, which ij 
 carries with it the superabundance of the acidulated layer. ( 
 
 Finally, it is strongly rubbed with a rather firm pledget of cot- ! 
 ton, in order to give the best polish. | 
 
 It is not necessary often to renew the pledgets of cotton imbibed | 
 with oil and rouge ; they must only be kept free from dust. I I 
 have said above, that the first preparation of the plate may serve | 
 indefinitely ; but it will be comprehended, that the second must I 
 be modified, according to whether we operate on a plate which has | 
 received a fixed or an unfixed impression. | 
 
 i 
 
 On the Fixed Impression. | 
 
 The stains left by the washing-water, must be removed with 1 
 rouge and water, slightly acidulated wittj nitric acid (at 36“ F, at i 
 this season [April?] and less in summer.) t 
 
 Afterwards, the plate must be polished with oil and rouge, in I 
 order to remove all traces of the image. | 
 
30 
 
 The operation is then continued, as I have just described, for the 
 second preparation of the new plate, and beginning with the 
 employment of alcohol. 
 
 On the Unfixed Impression (hut whose sensible layer 
 HAS been removed IN THE ORDINARY MANNER.) 
 
 First, the plate must be rubbed with alcohol and rouge, in order 
 to remove the traces of oil which serve for receiving the foregoing 
 injpression. 
 
 We afterwards proceed, as indicated above, for the new plate, 
 beginning with the employment of alcohol. 
 
 Observations. 
 
 On Iodizing . — The colour of the impression depends on the tint 
 given to the metallic iodide ; it may, therefore, be varied at will. 
 However, I have found the violet rose colour most suitable. 
 
 For transmitting the iodine to the plate, the sheet of cardboard 
 may be replaced by an earthenware plate, deprived of enamel. 
 The iodine transmitted by this means is not decomposed; it is 
 useless, I may even say injurious, to heat the plate before exposing 
 it to the vapour of iodine. 
 
 Washing with Hyposulphite of Soda . — In order to remove the 
 sensible layer, the solution of hyposulphite of soda must not be 
 too strong, because it destroys the sharpness of the impression. 
 Sixty grammes of hyposulphite are sufficient for 1 quart of dis- 
 tilled water. 
 
 APPENDIX. 
 
 We subjoin the formula for making a few of the solutions used 
 in the Daguerreotype process ; but we must caution those who may 
 be ignorant of Chemistry, that some of the substances used, are 
 deleterious and corrosive, and that great care should be taken that 
 
31 
 
 they do not touch the person, dress, or surrounding objects. A 
 drop of Bromine, for example, accidentally thrown in^o the eye 
 might easily destroy the sight. 
 
 Chloride of Iodine. 
 
 The Chlorine is procured by putting pure oxide of manganese, 
 broken into small pieces in a glass retort, and pouring upon it 
 some hydro-chloric (muriatic) acid. The retort communicates 
 by a bent tube with a small bottle containing iodine, which it 
 promptly liquefies. When the resulting liquid becomes a bright 
 red, the operation is complete. The Chloride of Iodine should be 
 preserved in a bottle well stopped, a little white wax round the 
 stopper will prevent its adhering to the neck of the bottle. In 
 conducting this operation, precaution must be taken that the 
 Chlorine does not escape; this gas being highly deleterious. 
 
 Eau Bromee. 
 
 Add an excess of Bromine to pure water* in a bottle, shaking it 
 well for some minutes. To one part of this solution, add forty parts 
 water, and the mixture, of a bright yellow, is ready for use. 
 
 Bromide of Iodine. 
 
 In a bottle which holds about three ounces, put 30 to 40 drops 
 of Bromine, — the quantity is not very important. Add Iodine, 
 grain by grain, till the Bromine is saturated. The Iodine which 
 does not dissolve, may remain in the bottle. To one part of Bro- 
 mide of Iodine, add 200 parts water, and it is ready for use. 
 
 Gilding Solution. 
 
 The receipt for this solution, as given by M. Fizeau, the inventor 
 of this method of fixing, is as follows : — 
 
 Dissolve one part of Chloride Gold in 800 parts of water, and 
 four parts hyposulphite soda in 200 parts water, — pour the solution 
 of gold into that of soda, by little and little, shaking it all the 
 while, the mixture at first slightly yellow, soon becomes perfectly 
 limpid. This mixture may be bought ready prepared of the 
 Opticians. 
 
 * If you are nof sure of the purity of the water, add a few drops of nitric acid. 
 
32 
 
 Comparison of French and English Measures, 
 Measures of Weicfht. 
 
 Decigramme 
 Gramme 
 
 English Grains. 
 
 1.5433 
 
 15 4330 
 
 Avoid. Weight. 
 
 Decigramme . 
 Hectogramme 
 Kilogramme . 
 
 
 . . 0.022 
 . . 0.220 
 2.204 
 
 
 Measures of Capacity. 
 
 
 Li f re 
 
 IMPERIAL. 
 
 Galls. Pints. 
 
 Decalitre 
 
 
 1.4464 
 
 
 
 PHOTOGRAPHIC APPARATUS, 
 
 CHEMICALS, &c. 
 
 MANUFACTURED AND SOLD BY 
 
 THOMAS Sl RICHARD WILLATS, 
 
 INSTRUMENT MAKERS, 
 
 9 8, CHI1AP31DE, LONDON. 
 
 Agent for the Liqueure Hongroise or Hungarian Solution^ 
 Redman's Photogenic Paper ^ and Sensitive Solution. 
 
 T. & R. WILLATS solicit the attention of the Scientific 
 Public, to the Improvements they have recently introduced in the 
 Construction of the Photographic Camera, which enables the 
 Operator to obtain the focus with much greater precision, than by 
 any other arrangement.