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.
603. Where the special sepia solution is employed one may use the regular developing salts intended for black paper, heating the bath to 150° Fahr. The regular sepia developing salts, however, are recommended for best results.
605. The above are the two principal papers used, and while there are other sepia platinum papers manufactured, some of them giving very pleasing results, yet all are manipulated practically in the same manner.
Care Of Sepia Paper. Sepia paper is more easily affected by light than the black; therefore, greater care must be exercised in handling this paper, especially during printing.
Quality Of Negatives Required. Sepia papers require a thin, snappy negative. A negative hard and con-trasty will not make good sepia prints. On the other hand, a flat negative will give muddy prints. An ideal negative for sepia prints is snappy, but not hard, full of detail and delicate catch lights.
Printing. Print about one shade lighter than for black paper. Do not tint the whites. The safest method to employ would be to make a print and develop, fix and dry it. This will give you a line on the required depth of printing. Remember that sepia prints usually dry up two shades darker than they appear when wet. A print may look weak while wet, yet when thoroughly dry may be just right.
Margin Printing. Platinum prints, especially when made on the heavy grades of paper, are usually printed with a margin. For a 5x7 negative an 8x10 or 10x12 sheet of paper is usually used. The negative is blocked with an opaque paper cut-out, while the printing is done in a large frame. Some pretty effects are produced by printing a border of one or more tints in the margin. For instruction see "Dodging in Printing."
Developer. The developing salts are put up in crystal form, in different size packages, the smallest of which will make a 16 oz. solution, the largest 64 oz., or one-half gallon. These salts must be dissolved in hot water, the entire package being dissolved at one time. Complete instruction for dissolving accompanies each package. These instructions should be followed to the letter.
Developing. For Willis & Clements Sepia paper the developer must be used hot, about 150 to 180° Fahr. The higher the temperature of the bath the warmer the tone, and the more crispness will be obtained.
612. A good way to keep your developer hot is to place the developing tray on a gas or oil stove. The tray, of course, must be either porcelain or agate ware to stand the heat. Regulate the heat so it will keep the solution on the point of steaming, without boiling, during developing, and as hot as the hands can bear. Use plenty of solution. The heat will cause you to handle the prints quickly.