This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
171. For your first practice work with carbon printing, all the material required, besides your paraphernalia for manipulating the process, is a couple of dozen sheets of carbon tissue the size of the negative you wish to print from. We advise purchasing carbon-black for your first work. Besides the tissue procure half a dozen sheets of celluloid. Of course paper supports can be employed, but when using the paper supports for the carbon, should you meet with failures the supports will be ruined and cannot be used over again. With the celluloid, all that is required is to wash off the surface and use the same celluloid for the second attempt. For this reason, we recommend the use of the celluloid for first work at least.
172. Besides the celluloid, you will want some bichromate of potassium. A few ounces will be sufficient. The celluloid sheets should be white matt, and a trifle larger than the prints you want to make. For a 4 x 6 print made on a 5x7 negative, you should use 5 x 8 celluloid. This gives a larger safe edge and there is less danger of marring the print. You can get along with one hot water tray. In fact, any flat vessel in the shape of a tray in which you can heat water, is suitable for the developing tray. If but one tray is used, you must have some hot water in another vessel heated ready for use. A tea-kettle is a splendid thing to keep hot water in ready for use.
173. It is advisable to sensitize a few sheets of the tissue the day before you expect to use it. It is also advisable to make an actinometer according to the previous instructions given, as this instrument is easily made and can be used for all future work. For preparing your actino-meter. place your negative that you expect to use for making your carbon prints in one printing-frame, with a sheet of printing-out paper on it-Solio or any printing-out paper will do. At the same time place a piece of paper on your actinometer and place that in a printing-frame also. Place both in the light to print at the same time. When the paper is pretty well tinted on the negative, which will require from three to five minutes, depending entirely upon the the quality of negative employed, withdraw both frames and examine the print and if the highest lights are not yet tinted, again place out to print. Occasionally examine the print, and just as soon as the highest lights show a slight tinting and the image is fairly clear (like a good printed proof), then take both the frames in from the light. Examine your print on the actinometer. Note the highest number which shows a slight tinting of the paper. This number is your key and your future guide.
174. Place the carbon tissue on the negative in the printing-frame, at the same time place a new slip of proof-paper on your actinometer. Place both frames out to print. The carbon tissue, of course, do not disturb, as there is no visible image on it. That is why the actinometer is required, for when the print on the actinometer registers to the number of the required tint, then the carbon print is completely printed. To make this more clear, we will suppose that when testing the strength of your negative the actinometer registered a faint tint on No. 7 layer. Number 7 is then your key. Print the carbon until the new slip of paper placed upon the actinometer registers to No. 7-both the actinometer and carbon having been placed in the light to print at the same time. When the tinting has reached this number the carbon is completely printed.
175. You may then proceed to develop the tissue. It is better, however, to make two prints before developing. This will give you a better opportunity for experimeriting. When ready to develop, place your celluloid supports in a tray of cold water to soak for a few minutes. In another tray of cold water place the carbon tissue. The tissue will curl slightly. It will also become covered with air-bells (bubbles). These must be removed with a soft camel's-hair brush. Dip the brush in the water first-never touch a print with a dry brush. When the tissue becomes flat, which will only require a few minutes soaking in the water with the face side (black side) down, slip one of your celluloid sheets under the tissue and gradually draw the carbon on to the celluloid, with the black side next to the celluloid. This must be done under the water. The combined tissue and celluloid are then withdrawn from the water and laid on the squeegee plate and squeegeed in contact, after which they are weighted down and allowed to remain for fifteen minutes.
SERIOUS MEDITATION Study No. 4-See Page 355 Eva Godley Rolfe.
176. The print is now ready to strip. Place it first in a hot water bath about 80° Fahr., and when the print shows signs of considerable oozing out at the edges, this will indicate that the thin layer of gelatin over the pigment is sufficiently softened and the back can then be pulled off from the pigment with one straight pull, thus leaving the image transferred to the celluloid. You then develop the print until the image appears clear and clean.
177. If the first bath of hot water at 80° is not sufficiently hot to develop the print, make a new bath 100° to 110° Fahr. and complete the developing in this bath. It is really better to increase the hot water gradually, as to jump from 80° to 100° is liable to produce blisters. Therefore, we advise that the fresh hot water bath be first made 80°. After the print has been in the tray for a few minutes, gradually increase the temperature, thus avoiding failures.
178. When the print is entirely developed it is then passed through the alum bath, after which it is rinsed in plain water and is ready to hang up to dry. Your first two or three experiments will prove a splendid guide for your future work, even should they be partial failures.
179. By consulting the Difficulty Department, you will readily find the cause, prevention and remedy for any failures met with. Always save first prints, and having observed the appearance of the prints during each operation, note on the back of the test prints all data pertaining to their production, and file them in the proof-file for future reference. Practice work for the following lessons on carbon printing should be carried out in the same manner, always saving first efforts, noting all data regarding manipulation on the backs of the prints, also filing them in the proof-file for future reference.