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.
Clearing. Sepia paper, being more sensitive to the light than the black, may be affected by the light when in the acid bath. Therefore in the first acid bath they should be placed face down. As the highlights may become tinted it is, therefore, a good plan when clearing the prints in the remaining baths to use gas or lamp light, or at least subdued daylight. There is also danger of damaging prints by allowing them to remain too long in the acid baths. Give sepia prints three changes of acid clearing and then wash exactly the same as for black and white prints. Sepia prints should not be allowed to lag in the various manipulations, as they lose brilliancy by long soaking. They should be handled as rapidly as possible through all the baths and dried between blotters.
Angelo Sepia Paper. While "Angelo" sepia paper is a cold developing paper, the printing and all other manipulations up to the development are exactly like "W. C." The developing salts must be dissolved in hot water, but after doing so the developer should be allowed to stand until cool. Filter before using. The print is developed exactly like the black paper. If warmer tones are desired, add to regular sepia developer some of the special "Angelo" sepia solution supplied by the manufacturer. The amount of sepia solution added regulates the warmth of tone. If thick paper is used you must leave it longer in the developer. It is better to first print a little under than over, as with "Angelo" paper the longer you leave the print in the developer the better the deposit of chemicals on the print. Therefore, prints not printed too far, will stand long developing and improve in quality.
Clearing Bath. The clearing, or fixing, of "Angelo" paper is exactly the same as for W. C. except for the use of a weaker acid bath. The acid bath for "Angelo" paper should not be stronger than 2 drams acid to 80 ozs. water. Be sure and do not carry any of the acid bath into the developing bath on your fingers, as the acid will not only retard the developing, but in time bleach the highlights.
623. Note. Keeping the Developer. - The sepia developing bath, after use, must be kept in the dark. A safe precaution is to wrap the bottle containing the bath with black opaque paper and label "Sepia Cold Developer." The sepia bath must not be used for black prints.
Constant Use Of Sepia Developer. Sepia developer can be used over and over as long as it gives good results. Should the sepia bath evaporate the crystals, they may be re-dissolved by adding water, restoring the bath to its original quality. Too much special sepia solution will produce bleached prints. Over worked sepia bath will also give bleached prints. Leaving too long in the acid bath, or in acid too strong will give bleached prints.
Caution. To avoid exposure to light, greater care must be exercised when developing and examining sepia than black and white paper. As it is more sensitive to light than the black, if exposed too long the whites will become discolored. Keep prints, while in the developer and acid trays, in subdued light. Discoloration of the whites is generally due to one or all of the following causes: First, exposing to light too strong while developing. Second, using a developing dish in which the enamel is cracked or chipped, exposing the iron. Third, old paper. Fourth, exposing prints while clearing to strong light. It is advisable to do your developing in very subdued light