é N.Y. i | v= => “3 Sey BS = Pe higtios : a 1 hates = a | on 3 — 5 a eee Fame ws | g | Oo | ol Ea a Fmd Kodak C chester oc and Filters olor Films, Color Films, Plates and Filters for Commercial Photography Eastman Kodak Company Rochester, N. Y. 1925 Introduction VERY photographer who photographs colored objects should know how to make negatives that will faith- fully record the monochrome values of the colors. Whether the subject is in one color against a background of another color or whether it contains two or more colors, he should be able to determine, from an examination of the subject, whether it is necessary to use color sensitive materials and whether an orthochromatic filter should be employed or a panchromatic film with either an ortho- chromatic or a contrast filter. Photographs that faithfully produce»in monochrome, the relative brightness of the colors of the subject are an absolute necessity for catalogue and book illustrations and for use byssalesmen who cannot earry sans of the objects the photographs represent. ~ * | The making of such photographs is a comparatively simple matter when once the principles involved are under- stood and in this booklet we undertake to make these prin- ciples clear. Should any question arise in connection with the subject, that we have not answered in these pages, we will be glad to deal with it by correspondence. EASTMAN KODAK COMPANY, ROcHESTER, N. Y. December, 1925 Photographing Colors ROM the earliest days of photography it has been rec- ognized that the effect obtained when colored objects are photographed is different from the effect which the objects produce upon the eye. This knowledge, indeed, has spread to the general public to the extent that it is common to hear dress colors described as ‘‘difficult to photograph,”’ while in general the satisfactory reproduction of colored objects for catalogue illustration and- other commercial purposes has been a most serious problem for the technical photographer. What the commercial and technical photographer requires is a means by which he can reproduce, in monochrome, any colors in any relative brightness which he may desire, and this can be obtained only by using films or plates that are sensitive to all colors, in connection with a series of color filters suitable for the whole range of colors likely to be met with in practical work. For this purpose, we manu- facture Eastman Panchromatic Films and the Wratten Pan- chromatic Plate, these being used with the Wratten Filters. These panchromatic materials are distinguished by the fact that they are completely sensitive to all colors. Or- dinary films and plates are sensitive to blue, violet; and ultra-violet. Those which are known as ‘‘orthochromatic,’’ in addition to being sensitive to these colors, are sensitive also to the yellow-green, and since this is the chief com- ponent of yellows, they are generally said to be sensitive to green and yellow. Panchromatic materials, however, are sensitive not only to the blue, violet, green and yellow, but also to orange and red, so that they are sensitive to all colors which the eye can see. Suppose that a photographer wishes to photograph labels printed in red, green and blue (see p. 15). Then an or- dinary film will photograph the blue as light, the green and red, dark; by using an orthochromatic film the green 3 CoLor FI_tMs, PLATES AND FILTERS will photograph light as well as the blue, but only by the use of a panchromatic plate can the red be photographed as anything but black. It will be realized that red sensitive - materials cannot be developed or handled in the ordinary darkroom light. A special safelight must be used, or no light at all. Eastman Commercial Panchromatic Film has nearly twice the speed of Eastman Commercial Ortho Film but has been specially sensitized to the red as well as to the green and yellow. The Wratten Panchromatic Plates are made in two varieties. The faster plate, of softer quality, is called the Wratten Panchromatic, while a slower plate, of greater contrast, is termed the Wratten Process Panchromatic, this latter plate being intended for use where great contrast is required, as in photographing labels, or for the preparation of the line and halftone negatives in photo-engraving. Therefore these panchromatic materials especially the Eastman Commercial Panchromatic Film are fast enough for general work even when filters are used. In fact, under some conditions the Panchromatic Film is faster than the non-color-sensitive materials. Although the Wratten pro- cess Panchromatic Plate is somewhat slower its ability to build up great density makes it a very useful plate. The Need of Light Filters By using panchromatic materials we can photograph a scene or object so that every color is given its correct relative value in monochrome, but in order to do this a filter must be placed in front or back of the lens. The reason for this is that even panchromatic materials are more sensitive than is the eye, to blue and violet light, in comparision with green and red light, and the way to pre- vent these colors from exercising an undue effect upon the plate is to use a colored filter which will sufficiently subdue them before they reach the plate. : + For COMMERCIAL PHOTOGRAPHY This filter must be accurately adjusted to the sensitive material. It must be sufficiently dark to stop the correct proportion of blue and violet light, and especially it must stop all the invisible but very active ultra-violet light, but it must not absorb too much blue light or quite all the violet light, because otherwise these colors will be repro- duced too dark. Three orthochromatic filters, designated by the letter “‘K’’, for use with panchromatic films and plates, give the photographer complete control over the degree of orthochromatic correction desired and these are sold by us either singly or in sets. The K1 is a pale yellow filter requiring only 50% more than the unfiltered exposure. The K1 filter should be used where only a slight correction is needed or where the ex- posure must be kept down to a minimum. The K2 is the most generally useful filter. It increases exposure on a panchromatic film or plate about three times, and gives excellent color reproduction. It is the most suitable filter for general work. Where the equipment is limited to only one filter the K2 is the one we recommend. The K3 filter gives a fully corrected color reproduction and requires about four and one-half times the unscreened exposure on panchromatic films and plates. It is not recommended for use with other materials. The Reproduction of Color Contrasts To the eye, objects are distinguished from their sur- roundings by contrast which may be of two kinds. It may be a tone contrast or a color contrast. Tone contrast can always be correctly reproduced photographically, but the result of the reproduction of a color contrast will depend on the photographic method used. Consider, to illustrate, two objects one placed upon the other and distinguishable from each other by the eye solely upon their color contrast—such as a bright red apple in a cluster of green leaves. The color contrast to the eye is 5 CoLor FILMS, PLATES AND FILTERS marked, although the tone contrast is small, that is, one color is really as dark as the other. Photographed with an ordinary film or plate both reproduce dark and, instead of contrast, a mass of black is recorded. If, now, a pan- chromatic material is used, with the K3 filter, both colors are reproduced in the same tone values seen by the eye: the contrast disappears and the colors are represented by a uniform field of gray. ) What, then must be done to obtain a satisfactory re- production of this color contrast? It is quite clear that it is impossible in the case suggested to reproduce the color contrast in a photograph so long as tone values are correctly recorded, consequently we must sacrifice the correct ren- dering of either the red or the green. If a green filter is used the green will appear lighter and the red darker; if we use a deep orange filter, the red may be lighter, the green darker; and which shall be used must be governed by cir- cumstances. If we over-correct the color contrast, it is usually better to over-correct towards the red (making a bright red, lighter) since red, as a rule, seems to us more brilliant than green. Again, with perfect orthochromatism, a yellow straw- stack against a blue sky may give a result, in which the strawstack cannot be distinguished from the sky. Here again it would perhaps be better to over-correct, though the individual must decide for himself in each case whether color contrasts shall be partly corrected, fully corrected, or over-corrected. The procedure we have been describing enables us to indicate color contrast, though it is a departure from true orthochromatism. For COMMERCIAL PHOTOGRAPHY Color Contrasts for Special Purposes There is another case of the photography of color con- trast, which is to the commercial workers of as great, if not greater, importance and that is the photographing of colored objects to secure the best possible general results for advertising purposes. If it is desired to photograph a colored object as black, it must be photographed through a filter that will completely absorb the color of the subject. No rays of light reflected from it will then reach the plate and, as a consequence, it will be reproduced as though it were black. For example, consider the label shown on p. 15. If a red filter is used the blue and green will be absorbed and will photograph more or less dark, while the red is transmitted and photo- graphs so well that the white word “negative” is indis- tinguishable. If no filter is used, or if a green filter is used, the red will appear black and the black lettering consequently lost. In order, therefore, to properly show all the colors, together with the black and white lettering, it is necessary to use the K3 filter which gives a correct reproduction. But the examples with the red filter and without a filter show how certain contrasts could be obtained if necessary. The most important application of this method occurs in the photography of furniture, where the results are indeed gratifying. If a piece of polished red mahogany furniture is photographed on an ordinary film or plate, no trace of grain is usually visible. To this plate, both the red and yellow portions of the wood are black; to give increased exposure simply results in the appearance of a plentiful crop of ordinarily invisible scratches in the photograph. If, however, Eastman Panchromatic Films or Wratten and Wainwright Panchromatic Plates, are used with the “A’”’ (orange-red) filter, the results are entirely different; the scratches disappear and the grain of the wood comes up in i CoLor Fi_Ms, PLATES AND FILTERS the most wonderful way. In fact, so great is the difference that it may seem incredible, to those who have never used panchromatic materials. In all furniture-photography success depends chiefly upon the selection of the filter for the particular subject to be photographed. Where mahogany is to be photographed, in most cases the greatest contrast can be obtained by the use of the “‘A”’ filter, the orange-red color of this filter giving the strongest contrast between the lighter and darker portions of the wood, thus rendering the grain in the most striking way. It must be remembered when photographing furniture for the purpose of catalogue illustration, that the object of the manufacturer is to make the article appear as attractive as possible, and to do this the natural grain of the wood must be shown in the illustration. The furniture can be photographed before being varnished and rubbed, when the results, if not quite so accurate, are attained with much less exposure. The same technique is used. With yellow woods, such as oak, satinwood, and walnut a red filter is of little advantage, and the “‘G’”’ contrast filter, which is of a strong yellow color, will be found suffi- ciently deep. When photographing inlaid furniture, too much exaggera- tion must be avoided, and when we have inlaid mahogany of the Sheraton type, it is somewhat difficult to render in its full strength the red grain of the mahogany without at the same time showing yellow inlays too white. The matter must be compromised and the “A”, “G” or “K3” filter used, according to the particular subject and the effect required (See p. 16). The effect of the filter can generally be judged by simply looking at the subject through the filter to be used. For the most difficult cases of very dark, old mahogany or rosewood, it is sometimes necessary to use the ‘“F” (deep red) filter, but this must be regarded as a reserve power, only to be used when absolutely necessary, because 8 For COMMERCIAL PHOTOGRAPHY the manner in which it over-corrects all lighter tones is liable to give a general impression of exaggeration to the resulting photographs. Tapestries and carpets are usually photographed with a “K3” filter, but if they contain much yellow, red and also light blues, the results will be found to be too flat, and for such work the ‘‘A’’ filter is more suitable. If a green carpet, with a red design, is to be photographed, and it is desired to clearly pick out the red design from the general light green ground, the green ‘‘B’”’ filter will be found most suitable. But where an important piece of work is under- taken, it is generally advisable to try one negative with a “K2” or “K3”’ filter in order to get an orthochromatic rendering before using a contrast filter, as it is desirable to avoid over-correction unless the subject necessitates it. Subjects for which a correct orthochromatic rendering is particularly desirable are reproductions of posters, labels and other forms of advertising matter in colors. Posters, for instance, in which the figures of persons are outlined against a bright yellow ground, if reproduced upon an ordinary film or plate, will convince anyone that there are subjects for which the ordinary non-color-sensitive material may not prove all that can be desired. In copying maps, a ‘‘K3”’ filter must be used if the map contains several colors, but in those which more often come to the com- mercial photographer, such as real estate maps, a contrast filter is frequently required to accentuate some special color in the original. For photographing new houses, and indeed most architectural subjects, the ‘‘G’”’ filter with an Eastman Panchromatic Film will give admirable results, avoiding the full tone in which red bricks are too often reproduced, especially in dull or hazy weather. Sometimes it is necessary to copy a print which has be- come yellowed with age. As ordinary films or plates are sensitive only to the blue, violet and ultra-violet rays, which are more or less absorbed by this yellow paper, 9 CoLor FILMs, PLATES AND FILTERS if a negative is to be made of such a print, the yellow paper will appear dark or gray. If a color sensitive material is used, with a yellow contrast filter, the yellow stain will have no effect and will fail to photograph. It should be noted that the yellow filter to be used for such a purpose should not be an orthochromatic filter, if the best results are required, but one which is much stronger, such as the Wratten “G’’ filter. An orthochromatic filter is made to photograph objects in their tone values, as seen by the eye, and if the yellow stain is visible to the eye, it will also photograph through the orthochromatic yellow filter. If the yellowed print be examined through the strong ‘‘G” filter, the yellow stain of the paper will not be visible. Sometimes however a better result may be obtained with an ordinary plate—it depends upon the nature of the print. The illustrations on page 18 show photographs of a print which had been splashed with a yellow dye, leaving a conspicuous stain. In the first photograph, made on an ordinary film, the stain appears quite black, while in the second one, for which an Eastman Panchromatic Film and the ‘‘G”’ filter were used, the stain has disappeared. Another difficulty is encountered in copying prints that are of a brown color, such as found in Sepia, D.O.P., Carbon or re-developed Bromide prints. This brown color has a very strong absorption for the violet light, to which the plate is sensitive, consequently such prints when photo- graphed give negatives having too much contrast or without detail in the shadows. It will generally be found that increasing the exposure will not satisfactorily reproduce such photographs. The obvious course is to photograph them as they are seen by the eye; that is, by means of a fully correcting (K3) filter and a panchromatic film or plate. A difficult task, without the proper plate and filter, is the photographing of engineers’ or architects’ blue prints, as it is impossible to obtain satisfactory results by using the ordinary plate. Nor can orthochromatic films, with 10 For COMMERCIAL PHOTOGRAPHY yellow filters, give the best results, owing to the fact that a great deal of the yellow-green light to which such films are sensitive is reflected by the blue print. Therefore, in order to obtain really first-class results, the “A” or the “F” filter should be used with Wratten Process Panchro- matic plates, thus photographing the print by red light, which completely absorbs the blue. With such a plate and filter, the negatives made from blue-prints are in every way as satisfactory as could be obtained from photographing a black and white print in the ordinary way. The photography of purple or violet typewriting can be accomplished in the same manner, by the use of the Green “B”’ filter and the Wratten Process Panchromatic Plate. Not only is the purple typewriting reproduced, but any corrections in red will also be shown as black, while if a red filter is used red ink will disappear. The commercial photographer often receives orders for prints that are to be colored by hand—to show the colors of the subject. In such cases his work will be much easier if the negative is made with a ‘‘K3”’ filter on a panchro- matic film. It is impossible to make either a colored print or a colored lantern slide correctly reproducing a subject containing yellows and reds from an ordinary negative. The ordinary plate shows these colors too dark, but the panchromatic film used with the “‘K3”’ filter will faithfully photograph all colors in correct relationship to each other, and a print from such a negative can be colored so that the colors will accurately reproduce the colors of the subject. We can put this whole matter briefly in another way by saying that white light is a combination of all the colors of the spectrum. Objects appear colored because they absorb all the colors of the spectrum except their own, which they reflect, so that a Red object absorbs blue and green light; a Green object absorbs blue and red light; a Deep Blue object absorbs green and red light; a 11 CoLor FILMs, PLATES AND FILTERS Yellow object absorbs blue light; a Magenta or Purple object absorbs green light; a Light Blue or Blue Green object absorbs red light. If a colored object is looked at or photographed through a filter of a color which it absorbs, it appears or photographs dark, so that with a blue filter red, green and yellow ob- jects all photograph dark and blue, light; blue-prints photo- graph like black-and-white prints through a red filter; typewriting (purple) through a green filter, and so on. If a colored object is looked at or photographed through a filter of its own color it appears light and any markings appear well defined. Golden oak shows its grain best through a yellow filter, red polished mahogany through a red filter. Films and Plates From the point of view of color-sensitiveness there are three kinds of sensitive materials: (1) Ordinary materials, such as Eastman Commercial Films, give the same monochrome rendering of colored objects that we see when we look through the deep blue (“‘C’’) filter. They are sensitive only to blue and violet light and are but little affected by green or red light. (2) “Ortho” materials, such as Commercial Ortho Films, when used without any filter, give almost the same rendering of colors as ordinary materials except that they are more sensitive to yellow. But when used with a yellow filter they reproduce yellows and greens quite well, so the various colors are recorded in nearly the monochrome values we see when looking through the green (‘‘B’’) filter. (3) Panchromatic films and plates are sensitive to all colors, but when used without any filter, blues photograph too bright. To get tones rendered correctly a ‘‘K3’’ filter must be used and this will suitably record all colors in monochrome. Only panchromatic materials can be used with Red or Orange filters. 12 FoR COMMERCIAL PHOTOGRAPHY List of Wratten Contrast Filters The set of light filters for general commercial work con- sists of eight filters, ‘‘K1,”’ ‘‘K2”’ and ‘“K3”’ being ortho- chromatic filters, and ‘‘G’’ a deep yellow filter for contrast work; “A,” “‘B,” “C”’ being the standard tri-color set and “F” a deep red filter for special work. The orthochromatic material referred to is Eastman Commercial Ortho Film. “Multiplying factor’ is the number the exposure without any filter, must be multiplied by to give correct exposure. These figures are only intended as rough indications of the increase in exposure which the use of the filter will entail; the exact factors for the filters vary with each batch of emulsion and are shown on a card enclosed in each box. Approximate Multiply- ing Factors For Eastman Panchromatic NAME USE Films and For Wratten Pan- Ortho- chromatic chromatic Plates Materi “K1” Very Light As a correcting filter when short Yellow exposure is of greater impor- tance than full correction. 1% 3 “K2” Light Yellow For general work with Ortho plates and films. The best single filter for panchromatic materials, 3 6 “K3”’ Yellow To obtain full correction with panchromatic films and plates. 44 12 “G” Strong Yellow To obtain detail in subjects where the contrasts are in yellow color—such as oak furniture. 6 30 “A” Orange Red Used only with panchromatic materials. To obtain contrast and detail in subjects of yel- low and brown—such as ma- hogany furniture. 12 *“‘B” Green For photographing typewritten letters and rendering greens light and reds dark. 10 12 “C’’ Deep Blue To photograph blue as white; greens, yellows and reds dark. 10 5 “F” Deep Red To photograph blue-prints and reproduce reds light. 24 Us CoLor FILMs, PLATES AND FILTERS Kinds of Filters Wratten Light Filters are supplied in two forms—the gelatin film filters, which are not protected by glass, and the glass filters, in which the gelatin filters are cemented be- tween pieces of optical glass. Gelatin film filters are. used mostly for experimental work. For regular work they are not recommended, as the film is easily marked by the fingers and the filters are apt to deteriorate on prolonged exposure to the atmosphere. Gelatin film filters may be fitted be- tween the lenses or held in a cardboard frame that can be fitted over the lens mount. It is best, however, for regular work to use filters that are cemented in glass. Glass filters are made circular to be fitted in slip-on cells and also square of any size desired. Filters in ‘“‘B”’ glass, two inches, three inches, and four inches square, can be used in our Adjustable Filter Holders. The two-inch filter holders are for use on lens mounts measuring from one and one-eighth to one and nine-six- teenths inches outside diameter. The three-inch filter holders are for use on lens mounts from one and eleven-sixteenths to two and three-eighths inches diameter, and the four-inch on lens mounts from two and three-eighths to three and seven-eighths inches outside diameter. The adjustable Filter Holders will be found especially desirable by all who use several filters, or several lenses on which filters are to be fitted. The filters can be inserted and removed instantly. We carry a full assortment of all ordinary sizes of filters mounted in slip-on cells. For this form of fitting it is neces- sary to send us the outside measurement of the lens barrel, and this measurement must be made very exactly. If a pair of sliding calipers cannot be obtained a strip of hard writing paper should be wrapped around the lens so that the ends over-lap and then the two pieces of paper, where they just over-lap, should be cut through, while in position, with a sharp knife. 14 PHOTOGRAPHS OF A LABEL EASTMAN yh NU iW iti niet Facsimile of Original PANCHROMATI FILM FOR MOTION PICTURES. Commercial Film Commercial Panchromatic Without Filter Film and Red “ A”’ Filter Commercial Panchromatic Film and “K3” Filter 15 PHOTOGRAPHS OF FURNITURE Facsimile of Original Eastman Panchromatic Film with “K3” Filter 16 PHOTOGRAPHS OF A ROSE Facsimile of Original Commercial Film Eastman Panchromatic Film Eastman Panchromatic Film with “G” Filter with “A” Filter 17 PHOTOGRAPHS OF VELOX PRINT WITH YELLOW STAIN Commercial Panchromatic Film with ‘‘G”’ Filter 18 For COMMERCIAL PHOTOGRAPHY Quality of Glass Filters Wratten Filters are supplied cemented in two qualities of glass plates, ‘“‘A’”’ glass and ‘‘B”’ glass. Wratten Filters cemented in ‘‘A”’ glass are known as Flats. ““A”’ glass is ground with the same accuracy as the best anastigmat lenses, and the completed filters are about one-half inch thick. Flats are recommended whenever long focus lenses are used, for three-color process work, where successive ex- posures must be made without changing the focus of the lens; in telephotography, and also in all cases when the very best obtainable results are desired. | “B” glass is selected from the best quality of optical plate glass. Wratten filters in ‘‘B”’ glass are most exten- sively used and are suitable for all ordinary commercial and landscape photography. We do not carry holders for “A” glass filters in stock, but make them to order. Developing Panchromatic | Films and Plates Darkroom Methods There is no doubt that the greatest obstacle to the use of red sensitive materials is the belief that it is difficult to develop them. This belief is chiefly due to the conservatism which instinctively shrinks from any change in the methods to which photographers are accustomed, but we actually find that most people who have accustomed themselves to the use of panchromatic materials experience no difficulty whatever, and even prefer the new methods to those which they formerly used. There are two methods of developing panchromatic films or plates; they may be developed in a developing tank or covered tray, using the safelight merely for seeing dishes, 19 CoLor FILMS, PLATES AND FILTERS etc.; or they may be developed in an uncovered tray a few feet from a Wratten Series 3 Green Safelight. For either method it is convenient to obtain one of the Wratten Series 3 Green Safelights. These safelights are made on the follow- ing principle: The eye is sensitive to all colors if the light is sufficiently bright, but as the intensity of light becomes less, the eye becomes less sensitive to red; and proportionately more sensitive to green; when the green light is very faint, it will be much brighter to the eye than any other light by which it is safe to develop. When developing a film or plate sensitive to all colors, we must use the light by which we can see the most with the least possible tllumination, and this condition is realized by the green safelight. These safelights are made of a sheet of glass coated with a bright yellow gelatin film and another sheet coated with a bright green film, bound face to face with a thick sheet of green paper between, the colors being spectroscopically correct. Wratten Safelights The various kinds of Wratten Safelights are made with scientific precision. The colors must be, and are, exactly adjusted by us in the spectroscope and by trial with the plates. But it should be remembered that no light is really “‘safe’”’ if the sensitive plate is exposed to it long enough. The standard we have adopted is an exposure of the dry, sensitive material, for which the safelight is designed, for 4% minute, 3 feet distant from the lamp, the illuminant being a 10-watt lamp if used in the Eastman or Brownie Safelight lamps, and 25-watt if used with the Kodak, or Wratten Safelight lamps. The material is less sensitive when wet. Exposure to the safelight in excess of this amount should not be given if fog is to be avoided, but more exposure may be given if the illuminant is weaker. When you first turn out the white light in a darkroom 20 FoR COMMERCIAL PHOTOGRAPHY where there is a green safelight, you will scarcely see the light itself, but if you wait a few minutes, most objects near the light will become plain, and at the end of fifteen minutes you will probably have doubts as to the safety of the light, which has become quite bright. These safe- lights are 3/16 of an inch thick and can be made in any size. If the safelight gets very hot, the film will crack off the glass, so that lamps for safelights must be well ven- tilated. We have designed a special lamp, the Wratten Safelight Lamp, which transmits only reflected light and is properly ventilated. It is described on page 31. Darkroom lamps fitted with ordinary safelights are not safe for these emulsions and red light must be absolutely avoided. Developing An instruction card is placed in every box. This card is printed in our factory, after actual tests of each batch of films or plates have been made in the laboratory. The card gives the particulars for tray and tank development, the time for both being given at temperatures of 50°, 65°, and 80° F., without danger of frilling. For temperatures in be- tween those given, develop for an intermediate length of time. The time of development necessarily varies for different batches. The correct time of development for both the tank and tray methods is stated on the instruction card packed in every box. This time is suitable for negatives that will print well on Vitava paper, but may be modified to give stronger or weaker negatives to suit the individual workers by increasing or decreasing the time of develop- ment, using our figures simply as a guide. If tray development is to be used, have your developer ready and a large cover that will completely cover the tray, permitting no light whatever to enter. Pour on the developer and immediately cover the tray, rocking it gently during the time of development. If a green safelight is not used, it is necessary to work in absolute darkness. Zt CoLor Fi_tmMs, PLATES AND FILTERS For ordinary contrasts, using Eastman Commercial Pan- chromatic Films or Wratten Panchromatic plates, Formula D-1 developer is recommended. Pyro-Soda Developer Formula D-1 Avoirdupois Sodium Bisulphite or Potassium Mee er ey. Pein : : . ok eas Potassium Bromide... .°.... . =. nr ers. Water, to make... es wy Sa B Water a ye a a ae Sodium Sulphite (E. KC. ) PME C Water, : 2 ig ee Sodium Carbonate (E. K Co: hs MEE ae en For use dilute as follows: Tank Development— Take 514 ounces each, A, B and C and add water to make one gallon. Tray Development— Take 1 part of A, 1 part of B, 1 part of C, and 7 parts of water. For developing Process Panchromatic films and plates Formula D-11 is recommended. Elon-Hydroquinone Contrast Developer Formula D-11 Hot water (about: 125° F.) 2°. 3. 4. Elon 0. 2. a Se Sodium Sulphite (E. K. Co.) ~% . | 2) Hydroquinone . toe vw a Sy Rae ee a Sodium Carbonate (E. K. Co.) . 4 oo 34 02. Potassium Bromide. . 2a a Ee Cold watertomake . . . Mr Use full strength at 65°. For ee contrast, dilute with an equal volume of water. 22 For COMMERCIAL PHOTOGRAPHY Fixing If you use the following acid fixing bath the light can be turned up after fixing has proceeded for three minutes. Acid Fixing Bath (Formula F-1) Hypo RIE Sea al ed oe ee Ee ees 4416 ..0Z8; Water , le 64c0zs. Dissolve, and add the following hardening solution: Water Ce Mere 18 ee Ow ae Pelky anee ide eyrae Sodium Sulphite (E. K.Co. w a, oa Tht aos Cae ees Os Acetic Acid (28% ure). Po iiy yk at FT) 9? eye hy os toad Sen OLS Potassium Alum : MR Metra to SMe 2 tLe tee ae ee SOF. If you prefer ‘io or alkaline hypo, no exposure must be made to the light until fixation is complete. Always use fresh, strong and clean fixing baths. Old and discolored ones are sure to produce trouble. With the Wratten double coated plates thorough fixing is important, and the plates must not be removed from the fixing bath until it is certain that they are completely fixed. To make up the hardener, dissolve the chemicals in water at about Ioo degrees Fahrenheit in the order given above. The sodium sulphite should be completely dissolved before adding the acetic acid, after the sul- phite-acid solution has been thoroughly mixed add the potassium alum. Pour the hardener solution slowly into the cold hypo solution while stirring the hypo solution rapidly. The hypo should be thoroughly dis- solved before adding the hardener, otherwise a pre- cipitate of sulphur is likely to form. For those who prefer a chrome alum formula, the following is suggested: Chrome Alum Fixing Bath for Films and Plates (Formula F-16) Pe wOm ee Not ee hon ol i ae ee 2b, Prema ouiniite (bs Kh. Co.) wn. Od ar fa 2 ZB. Water to make 96 ozs. Zo Cotor Fitms, PLATES AND FILTERS Bo Water oes ite OE rl ee eee Potassium Chrome Alum . . °. . ..°. 9 2.025 Sulphuric Acid—pure conc, . >... 4, 9) ee Pour B solution into A solution slowly while stirring A rapidly. This formula is especially recommended for use in hot weather, but it loses its hardening properties in a few days either with or without use, and therefore should be used as soon as possible after mixing. This formula, when fresh, hardens the film more thoroughly than the potassium alum formula, and is, therefore, to be preferred in hot weather, but it should be renewed frequently. Formula F-1 gives satisfactory hardening throughout its active life and as an all around bath is to be preferred. Hardening Baths In hot weather the following hardening bath should be used after development and before fixation in con- junction with Formula F-1, or when the bath F-16 does not harden sufficiently. Chrome Alum Hardening Bath for Films and Plates (Formula SB-3) Water: 0005 © 2 a Potassium Chrome Alum . . eh es 1 oz. After development rinse the films or plates for one or two seconds and place for two or three minutes in the above bath. Agitate the films for several seconds on first immersing in the hardening bath, otherwise a chromium scum will tend to form on the film, which is very difficult to remove. Then place in the fixing bath. Trouble from stains, blisters and airbells is largely prevented if the film or plates are agitated on first immersing in the fixing bath, and at intervals until fixation is completed. This hardening bath 1s a blue-violet color by artifical light, when freshly mixed, but it ultimately turns yellow- 24 For CoMMERCIAL PHOTOGRAPHY ish-green with use. It then ceases to harden and should be replaced with a fresh bath. A freshly mixed and unused bath will keep indefinitely, but the hardening properties of a partially used bath fall off rapidly on standing for a few days. It is very important to observe the precautions re- garding agitation of the film on first immersing in the hardening bath in order to prevent the formation of chromium scum. The scum is produced by the action between the chrome alum and the alkaline developer carried over on the film, but it does not form if the bath is acid. If the film is not agitated the hardener solution in immediate contact with the film becomes alkaline and it precipitates a chromium hydroxide tends to form. Agitation of the film will prevent this. When the bath becomes old, a scum will tend to form even when the films are agitated. The bath should then be dis- carded. These films should always be washed with water and wiped with cotton after washing in order to remove any possible traces of scum because once the film is dry it is impossible to remove it. For full particulars for handling film under hot weather conditions, see the booklet on “Tropical Development.” The Importance of Rinsing When a film is transferred from the developer to the fixing bath, the alkali in the developer retained by the film neutralizes some of the acid in the fixing bath. When a certain quantity of acid has been destroyed in this way, the fixing bath precipitates white sludge, rendering it useless. The addition of developer also gradually destroys the hardening properties of the fixing bath. Therefore, by removing as much developer as 25 Cotor Fitms, PLATES AND FILTERS possible from the film by thoroughly rinsing in water, the life of the fixing bath is much prolonged, while the tendency for stains and blisters to form is very much reduced. In warm weather it is only possible to rinse for one or two seconds, otherwise the film will soften. If the chrome alum hardening bath above is used, rinsing in water may be omitted, although a previous rinse for a few seconds in water, will prolong the life of this bath also. The Life of a Fixing Bath A fixing bath is exhausted either when a sludge forms or when the fixing power of the hypo is reduced to such an extent that there is danger of some silver remaining in the film after fixing for the normal time. Sludging can be prevented by a thorough rinsing after develop- ment. The F-1 and F-16 baths above will completely fix the equivalent of 75—8 x Io inch films or plates per gallon of solution provided a thorough rinsing water precedes fixation. If the acid hardening bath is used, the fixing bath will not precipitate a sludge as readily, and the equivalent of 1oo—8 x Io inch films or plates may be fixed per gallon. Halation By the use of film halation is avoided. In order to prevent halation with the Wratten Panchromatic and Process Pan- chromatic Plates they are now made double coated. 26 For CoMMERCIAL PHOTOGRAPHY Technical Books on the Photography of Colors The Photography of Colored Objects, 102 pages, bound in board, (new edition) Wratten Light Filters, 82 pages (for scientific workers) Photomicrography, 44 pages Prices of Eastman Commercial Panchromatic Film Prices Include Excise Tax Size Per Doz. 314x444 ye 344x5% 1.03 eS 1.03 447x6% 1.50 434x6% P55 cs pio ae | 1.65 eS ae 1.96 614x8% 2.53 mel 3.14 be xii *3..66 se x 10 3.66 10 x 12 ‘ 6.39 Fa ed ; 6.39 11 x 14 : 9.18 Sx 20 é 9.48 12 x 20 nA oS 14 x 17 Et See 16 x 20 . 20.8 30 x 60 Size 17 x 20 13 30:22 20 x 24 20 x 26 22 x 24 20 x 28 yw ae 22 x 28 20 x 30 22 x 30 24 x 30 25 x 30 24 x 36 24 x 40 28 x 36 30 x 34 26 x 40 30 x 40 .pil7. Eastman Commercial and Commercial Ortho Film Prices Include Excise Tax ize Per Doz. 3x44 .67 3Y4x5% .93 A eS .93 4x6 1.34 434x6% 1.39 ae | 1.50 Ay 8 1.75 614x844 Dect 7: ox £0 2.84 (Meee Ba gi 3.30 ie om Y LS eat (4 27 37 1s CoLor Fitms, PLATES AND FILTERS Prices Include Excise Tax Size Per Doz. Size Per Doz. At ee «aie oe taba Dem gh oh i 24% 36... \ aes ZO OO A SARS ent ae 24x40. . 94°) eee De De ke Pe ee Le Oe 25 x 30... ee ee ee DONS l Mace, Ce eee aed say eae) 26 x40. « ieee DL nO Po ak eens yee eee 28 x36: 4. ee pe we os] | Wileemebeaibe 20g oe 39.12 30 x 34) 5) 5 ee 24, 8°30 0 tae 42.68 30 x 40 5 ee eae " 30 x 60. . $106. 70 The 5x7, 64x8% and 8x 10 sizes are put up in 2 dozen packages at $2.99, $4. 54 and $6.60 respectively. Nai epee sizes of Eastman Film will be furnished at approximately proportion- ate prices to the next larger size. When furnished in quantities of less than regularly listed packages, the price will be figured per sheet, at proportionately the rate per dozen sheet package, plus additional charge for packing, about 10 per cent. Prices of Wratten Panchromatic and Process Panchromatic Plates Double Coated Prices Include Excise Tax Size Per Doz. Size Per Doz. SRA ee Bae ee eee 10 x 12.4 fee Bhs wes BigKh a oe Wa eee Vote: 1.14 tl x 1473 | eo 10.40 eS 1g 144x17):.. 2. eee 44x64 tevt 12x20 “6 ) 30 (re , ats 1.86 16x20 ©. ° ¥ eee 6144x8% 2.85 18 x22. oie See x 10 4.14 20x 24° . - 5 ee I fo ee | 4.14 Wratten Filters Unmounted Gelatin Film Cemented in ‘‘B”’ Glass Circles or Unmounted Mounted in Squares in Inch Circles Squares Metal Cells A Glass 34 S20) St.15 Ysa 15 $2. 40 ae 1 .20 1.30 1.30 7.55 6.50 1% .20 eee nae 2 SY eee 1% .20 1.45 1.45 2.85 9.00 15; .20 ie fas 3.153 =e 13% .20 1.65 oe 3.15> 3 1% 25 1.65 1.65 3.35 11528 Zs aks Cte ieee 3.30 tees eee 1% .30 E75 3.303 ae 14 .30 ae Wick 345 ee eee 134 .30 1.90 1.90 3.45... $2 ere 1% 35 2.10 a 4.90) 3. 4 eae 14 635 amit te: ae 4,20.