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.
The Red-filter negative should be marked Blue printer. The Green-filter negative should be marked Red printer. The Violet-filter negative should be marked Yellow printer.
1193. The film is laid onto the negative with the un-coated side downward, so that the printing may take place through the celluloid.
1194. A print meter will assist in making the correct exposure, but the following is a safe and ready guide. The yellow film may be examined by artificial light, and when a faint image of the picture is visible upon it, then the blue film is sufficiently printed, and must be immediately transferred to a dish of cold water. The yellow film must continue to print until a pale brown image is seen, with a fair amount of contrast. The red film will require a little longer time; the average ratio of exposures being: Blue, 1; yellow, 2; red, 3.
1195. Under-exposure must be avoided, as it cannot be remedied in the after treatment, and greatly over-exposed films become so insoluble that they are difficult to develop satisfactorily.
1196. Note that all the exposed films must be transferred to a dish of cold water in artificial light, and after soaking for five minutes, the subsequent operations may be carried on by daylight.
Development. Flat porcelain dishes should be used for the red and blue films, and a black one for the yellow. Fill up the dishes with warm water, 90° Fahr., and immerse the films by sliding under the water; the surface of the film must not be touched with the fingers. When the films have been in the warm water for a few minutes, the dishes may be gently rocked, and the development of the picture watched. If fully exposed, the films will not completely develop unless the temperature of the water is gradually raised from 110° to 120° Fahr. Water that is too hot for the fingers of the operator will cause the celluloid to kink and the film to be spoiled.
1198. If after fifteen minutes' treatment development does not appear to make progress, a little liquid ammonia should be added to the developing waters. If correctly or slightly under-exposed films are agitated too severely during development, the details of the lighter tones will suffer. When apparently developed, the films should be transferred to a dish of cold water; this will arrest the development and make the films less liable to injury from handling. Having developed the three constituent prints, lay the yellow film on a piece of opal glass, or a sheet of plain glass, with white paper under it. Over the yellow lay the blue film, and on top the red one.
1199. The operator will now be able to judge as to whether development has been sufficient or not. If the print is heavy and dark, then the blue film will require further development; if too brown, probably red, or both yellow and red films are under-developed. The final result should appear to contain a little more yellow than necessary, because on drying the finished picture it is found that the yellow is greatly subdued by the overlying films. Having developed the set of films satisfactorily, pin up each one separately on a line to dry.
1200. Transferring the Yellow Print - When thoroughly dry, soak the yellow print in water at 80° Fahr., for fifteen minutes. The temperature must be kept up during the whole time of soaking. Then, into water at 65° Fahr., immerse a piece of transfer paper, face upward, for one minute, and bring the yellow film into contact with the transfer paper in this water. Lift out immediately and carefully rub down between blotting paper. A cloth is better than a squeegee for this purpose. See that all air-bells are removed, and then hang up to dry.
1201. If the film does not adhere to the paper at the edges, place the print between blotting paper and then between two glass plates, and stand a seven pound weight upon them for fifteen or twenty minutes.
1202. When the yellow print is thoroughly dry, a pin should be inserted between the celluloid and the paper at one of the edges; draw the pin along to one corner, and then along the second edge. Now, taking the loose corner, slowly strip off the sheet of celluloid. Clean the surface of the yellow print with benzine on a tuft of cotton-wool. Repeated rubbings and turning of the wool will be necessary in order to insure the entire removal of all the rubber solution with which the surface is coated. It is now ready for receiving the blue print upon it.