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.
Negative Drying With Too Much Grain. This is apt to happen with plates that have developed slowly. Long, continuous soaking will soften the film, and cause it to raise from the plate, and when it dries it will dry with a grain to the film. Another cause is due to previous soaking in the carbonate and sulphite bath. This opens the pores to an excess. Plates treated thus should be washed in running water for no longer than fifteen minutes and dried quickly either by an electric fan or in a room where there is plenty of air circulating. A good plan is to dry them at an open window, as this will give a free circulation of air, but you must be careful that the sun does not shine on the negative while drying, as the heat of the sun is apt to dissolve the film.
Yellow Negatives. Long soaking in the water; soaking in the accelerator with insufficient sulphite; poor carbonate or poor sulphite and prolonged development are apt to cause this yellowness. When the pores of the film have been opened to an extreme the pyro is apt to stain. As a general thing in an under-timed plate this yellow tint, if only slight, will do no harm, but rather adds strength to the printing quality. You can remove this yellow by treating with clearing solution, given in the instruction on Negative Reducing, Chapter X (Varying Water Conditions. Their Effects Upon The Manipulation Of Sensitized Papers).
Plate Developing Only Partly And Then Stopping. When the plates are badly under-exposed they will generally act in this manner. By adding a little more carbonate of soda, being careful, however, not to go to an extreme, the plate will continue to develop. When you find that the shadows are beginning to fog it is advisable not to attempt to develop any further, simply rinse and fix the plate. Applying a fresh developer diluted with four times the amount of water and allowing the plate to remain in this bath for fifteen to twenty minutes will bring out all the details possible to obtain with the exposure given.
Shadows Lacking Detail. If the plate is very much underexposed the shadows will lack detail, no matter how you treat them in the developer. You can improve them to some extent, however, by either breathing on these shadows during development - holding the negative close to the mouth - or laying the fingers on the shadows. This warmth of the breath or fingers will assist the developer in acting. You must be careful, however, not to lay the ball of the finger on too heavily, or it will injure the film. You can improve them considerable by the treatment given in paragraph 122.
Plate Frilling. If the developer becomes too warm, which might be the case in a very warm, dark room, or from the continued placing of the warm fingers in the developer, the plate is apt to frill. The excessive use of strong alkali (carbonate of soda), is apt to make the plate soft and frill. Under-timed plates, or plates which develop slowly, should be handled as little as possible, for the long soaking of the filmcauses it to soften and is, therefore, very easily damaged. See that your hypo is fresh and cold. After the plate has been fixed, rinse for a few moments, and place in a weak alum solution - decant half an ounce saturated solution of alum in ten ounces of water. This will harden the plate and overcome any frilling. Be sure and use only the decanted solution, for alum crystals coming in contact with the film will produce a purple stain. After hardening, wash thoroughly before setting to dry.