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.
Drying Tissue. If your drying-room is connected with a room supplied with some way of heating it, it would be well to allow the door of this room to remain open for several hours before using, so that the drying-room may become thoroughly dry and warm. As a hot room will cause tear drops by softening the gelatin film, be careful to select a room that is thoroughly dry, but not too hot-one connected with a room that can be heated is better. The carbon tissues, before sensitizing, will keep well for two months.
140. The sensitized carbon paper is about twice as sensitive as silver paper, and will remain in good condition for from three days to one week, if kept from the light. After the paper is thoroughly dry, place it in an ordinary plate box, one sheet laying on the other. After all are placed in the box, weight down with a piece of heavy glass, in order to hold them flat, as this paper is much easier to handle when perfectly flat. The paper is now ready for printing.
Masking The Negative. Your next step will be to prepare the negative to receive the carbon tissue. Cut out a mask of black opaque paper, such as is used in wrapping dry plates, or yellow post-office paper, the latter being preferable. The mask should leave a margin around a 5 x 7 plate of at least 1/2 inch. Paste the mask on the film side, making an opening 4x6 inches; smaller plates in proportion. This mask on the negative will supply to the carbon tissue what is known as the safe edge, which is absolutely necessary when making all carbon prints.
142. Lantern slide binding, or passe-partout tape, cut into strips about a quarter of an inch wide, may be placed around the negative. There is but one caution necessary, and that is against allowing the paper to overlap at the corners. If it does it may result in the breaking of the negative. The two strips should be neatly fitted together. A brush charged with India ink or other black paint or black varnish may be applied around the edge in a similar manner.
143. Another method favored by some carbon workers is to take a piece of clean glass, the same size as the negative, putting the "safe edge" on that. This glass is then placed in the printing-frame, so that the " safe edge " on it is in contact with the glass side of the negative when this is put into the frame. The advantage of this method is that one "safe edge" for each printing-frame in use will be sufficient, and it is, perhaps, the best plan of all.
The Quality Of Negatives. Different qualities of negatives require various depths of printing. The best negative for carbon prints is one that would make a good, snappy albumen print; hard negatives give contrasty results. A good negative is one quite thin and snappy, full of detail, and clear in the high-lights. Such a negative will yield most beautiful results. Flat negatives make flat prints, but few negatives are made exactly of the same quality; therefore, no two can be printed the same length of time. For this reason you must sort the negatives from which you expect to print, arrange them according to their different strengths and place them by themselves.
DAY AFTER ELECTION IN THE COUNTRY Study No. 3-See Page 355 John S. Neary.