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.
Recording Exposures. A good plan, after having ascertained the correct exposure for a negative, is to write on one corner of the film, with ink, the number of seconds required to print and the kind of light used. The initial letter is sufficient. In this way, when printing from this negative again you will not have to experiment to get the exact exposure.
456. Note: Always load the printing frame in diffused light, behind the cardboard or yellow postoffice paper screen; also develop by the same kind of light. Cover the box containing the paper immediately after loading the frame, as exposure to white light or even constant exposure to subdued light would ruin it. By following the above rule you will avoid fog and waste of paper.
Developing. Suppose that the exposure has been made and that everything is in readiness to develop the print. All trays having been thoroughly cleansed, place the tray labeled "developer" to the left, near the cardboard partition, a tray of clear water next, and the fixing tray behind the water. Fill the water tray a little over half with clear water; prepare the acid hypo bath in the fixing tray, then wash your hands thoroughly so as not to carry any trace of the hypo into the developer, and next pour enough developer into the developing tray to fully cover the print.
458. Use plenty of developer and keep it cool. Immerse the print - face up - sliding it underneath the solution quickly, and covering the whole surface of the print evenly with one sweep of the developer. Regular or carbon papers should be developed in about fifteen seconds. Should air-bells form on the surface of the print, when first placed in the developer, break them at once with a tuft of cotton, (kept on hand for the purpose), dipped in the solution, or with the tip of the finger. If not broken, white spots - undeveloped spots - will be left on the print. Never dip the fingers into the developer, after having them in the hypo, without first thoroughly washing the hands. To do so would ruin the developing bath. Always remember that hypo is a bitter enemy to all other chemicals, and a single drop of hypo in any other bath would be likely to ruin it.
Restrainer. If the high-lights (whitest parts of picture) are gray and the print has developed clear detail, it is apparent that sufficient exposure has been given, and the gray tone comes from too rapid development. The bath must, therefore, be restrained by adding a few drops of a 10 per cent. solution of potassium bromide to the developer. The 10 per cent. solution is made by dissolving one ounce of potassium bromide crystals in 9 ounces of pure water. Be very careful not to use more of the potassium bromide solution than is absolutely necessary to keep the whites clear, as an excess of the restraining agent will not only retard development and produce contrasty prints, but will produce greenish prints as well.