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.
844. While the practical making of sepia prints by direct development is a problem still unsolved, most satisfactory results are obtained by a process of bleaching and development. The process is extremely simple. Any print which has been properly fixed and washed, regardless of grade of paper (even prints that have been made for some time) may be changed to a sepia tone in a few minutes, without loss of detail in the highest lights, or change of contrast. The tone is governed principally by the printing quality of the negative. A print from a thin, weak negative will give a rather muddy sepia, while one from a negative of good strength will produce brilliant shadows and clear, mellow highlights.
Permanency. Prints toned in hypo alum have been proven permanent by thousands of users of bromide paper. Re-developing produces a result chemically identical to that obtained by the hypo alum toning, the print suffering no change in detail or gradation.
Uniformity. Following the directions given herein will insure absolute uniformity.
Rapidity. A print may be toned a sepia in less than two minutes' time, by the following re-developing process. The prints are first bleached until the deepest shadows have almost disappeared. They are then placed in the re-developing solution until all the detail has returned in the prints. Make up the stock solutions as follows: