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.
A Convenient And Systematic Arrangement Of Trays For Development. Convenience and system are quite an advantage in the successful manipulation of carbon paper. The following is a very convenient arrangement for trays: First, provide yourself with quite a long table. On the end to your left, place a tray containing clean, cold water. Next to the tray place the mounting or squeegee plate; then comes the developing tray or hot water tank. This tank can be an ordinary zinc tray, 8 x 10 inches or larger. A more convenient tank would be one 25 inches long, 4 inches deep, with a partition through the center, thus making two tanks in one, each tank 15 x I2 1/2 inches. In such a tank, carbon prints any size to 11 x 14 can be developed. This tank is arranged on stilts, about 10 inches above the table, or sufficient to allow a gas or oil stove being placed underneath.
344. Temporary stilts may be provided by using a couple of ordinary bricks under each end of the tank. The principal object of the double tank is to supply one tank of water heated to a higher degree of temperature than the other. The temperature of the one would be from 80° to 100° Fahr., and the other should be from 100° to 115° Fahr. By means of the heater and double tank, it will be very easy to increase the temperature of either or both baths instantly. If a single tray is used, heat the water in a similar way and have on hand a kettle of boiling water to be used to increase the temperature when desired.
245. To the right of the hot water tank, place another tray of cold water, in which to rinse the carbons before placing them into the alum bath, which latter is prepared in a zinc, or any other tray and placed next to the rinsing tray. From the alum bath the prints are again transferred to a cold water bath, temperature about 60° Fahr. In this bath the prints are freed from the alum and the operations are completed.
246. Now, that the trays are arranged in convenient order, we are ready for developing. First of all, if your transfer paper is in sheet form, cut the required number to the correct size, always allowing a half inch larger than the tissue. If they are small pictures, several may be mounted on one piece of support and all developed at one time. (We advise beginners to buy the supports cut to the correct size, all ready prepared, as they cost no more than if you prepared them yourself.)
247. Remember, the transfer must be made in subdued light. After the tissue becomes well water soaked and the bichromate is well washed out, very little of the sensitiveness remains; therefore, the greatest precaution must be taken during the transferring of the support. The developing may be done in more open light. Place your supports, whether paper or celluloid, or whatever they may be, face up into the first tray on the left, containing cold water. Allow them to soak for say 20 minutes, or long enough to free the paper from all air-bells. If any appear on the surface after twenty minutes, expel them with a soft camel's-hair brush. The supports now being ready, take one of the tissues that has been printed and immerse it face down in the same tray with the supports. See that the dust is removed from both sides of the tissue before immersing. This you do with a soft (dry) camel's-hair brush.
248. Never allow the tissue to be raised out of the water. Always keep the tissue under water, and when air-bells arise on back or front, remove them with the wet camel's-hair brush. Allow the tissue to remain in the water until the gelatin is sufficiently swollen that the print lays almost flat. You will find as soon as the print touches water it will begin to turn inward. This is caused by the paper expanding more rapidly than the gelatin film.
As soon as the gelatin film has absorbed sufficient of the cold water, it will flatten out, and owing to the gelatin having a greater expansion than the paper, as soon as the print is flat it immediately begins to curl the other way; therefore, as soon as the print is flat, and before it curls in the opposite direction, bring it in contact with the support by gently sliding the support under the print, or bring the print up onto the support. Do this with both tissue and support under water, and when you have the tissue properly located and in contact with the support, then withdraw both from the water and lay them on the squeegee plate, cover with a rubber cloth and apply a flat or drag squeegee, rubbing them from center to edge, first gently, afterwards more vigorously, to bring the tissue and support into perfect contact.
240. Instead of a rubber cloth a sheet of clear celluloid can be used. This will not wrinkle up like the rubber cloth is liable to do, and at the same time, the presence of air-bells between the support and the tissue can be better detected. A squeegee roller can be applied at this stage to assure more perfect contact. After the squeegeeing, apply a dry blotter in order to remove all the surplus moisture surrounding the print.
250. Next place the print, now in contact with the support, between two dry blotters (one below and the other on top), stacking several prints one over the other. In this way allow them to remain for from ten to forty minutes, according to the age of the tissue and the kind of a support used. Paper supports need less time than celluloid. Fresh tissue requires less time than old paper.
251. If there are a large number of prints to develop, or if for any reason you cannot develop all the prints within a given time, remove the blotters from between the prints and stack them together, thus keeping them moist until you are ready to develop them. In hot weather or in hot climates, the coolest possible place should be selected for making the transfers. The warmer the weather the shorter the time the prints should rest under pressure, and even then they should be kept in a cool place. The development, of course, can be carried on in any temperature, even a hot room. As the image is developed in hot water a sudden change to very cold water after development will affect the developed image.
252. The Development - When the carbon tissue has been under pressure the required length of time, it can be removed and immersed in the first hot-water bath, which should not be over 80° Fahr. To immerse the print in a bath of higher temperature at the start would cause the tissue to be covered with air-bells. These bubbles or air-bells are caused from the air being suddenly expelled from the tissue and support by the hot water. If any of these air-bells should become imprisoned, the picture would be ruined. Therefore, it is advisable to first immerse the carbon and support in a lower temperature bath, and allow it to become well soaked. This will require only a few minutes. During this time be on the lookout for air-bells, and, as they appear, expel them at once with a camel's-hair brush or any soft material that will not require any heavy pressure, as that would spot the picture.
253. The carbon and support should remain in the first bath until the dark pigment begins to ooze out around the edge of the tissue, which is a sign that the gelatin has become sufficiently soluble to allow the paper to be removed from the back of the tissue. Sometimes this takes place in three minutes, at other times longer, much depending upon the condition of the carbon tissue. If fresh it should not require more than three, and at the most, five minutes. By this time, if the pigment does not ooze out freely all around the edge of the tissue, transfer the print to the higher temperatured bath, which will bring about the desired results very quickly.
254. To make sure that the film is sufficiently soaked, squeeze the edge of the tissue gently with the thumb. If the pigment seems soft and oozes out more freely, then it is time to remove the paper or original support from the pigment film. You do this by taking hold of one corner of the thin paper and pulling slowly backward, taking care to keep the transfer under water. The paper being of no further use can be thrown away. The film at this stage must remain carefully under water and not be allowed to come to the surface until the sensitive bichromate has been quite well washed out and the picture fairly well developed.
255. The pigment remaining in the transfer after the original paper support has been removed is quite clammy, and the image is not yet discernible, but on continuing the development with hot water it soon becomes clear and entirely developed. This stage is reached when, upon lifting the print out of the water to drain, no trace of coloring matter is seen on the edge of the support when the water runs off.
256. After the paper support has been removed from the tissue, it is well to carry on the development in the lower temperature bath, until it is quite evident from the action of the warm water whether the tissue was correctly exposed or not. If the image begins to clear up very rapidly, the tissue has been under-exposed and a still lower temperature bath should be used immediately. This may save the print. If the removal of the paper on the back of the tissue, even when placed in water of higher temperature, is accomplished with difficulty, it is an evidence of the tissue being rendered partly insoluble by over-exposure in the printing. When this is found to be the case, raise the temperature of the water gradually until the paper will strip freely, then lower it to about 90°. When hot water at 120° or 125° Fahr. fails to have the required effect, the only remedy left is to apply a little alkali, such as borax, carbonate of soda, or the like, borax being the best. A few drops of a saturated solution of borax added to a separate tray of hot water, and the print placed in this bath for a few minutes, should produce the required effect.
257. If the time of exposure has been exact and the negative is not too thin, the developed image should be very brilliant. If, however, the exposure has been too short the shadows only will appear, the half-tones being washed away entirely by the warm water.
258. If the negative is too hard, the half-tones will disappear partially in the high-lights, but if the exposure has been too long, the image will not only separate from the transfer for the want of adherence, but the image will be quite pulpy. If a little boiling water is added to the warm water, making the bath 130° Fahr., the print, if left long enough, will generally become less dense. If only a portion of the image needs reducing, water heated to 130° in a kettle with a long spout, may be poured over the spot and the development concluded locally. After development the print is placed in a tray of clean, cool water for a few minutes, to stiffen the film before it is put into the alum bath.