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.
Drying Negatives. The warmer the air in which negatives are dried, the more intense they become. Negatives should be dried in a current of air. If more than two hours are consumed in drying, trouble may result, even if the temperature be moderate. Never move negatives from one place to another during drying, or marks will result.
744. When there is good printing detail in the shadows, but the highlights lack point and snap, too flat lighting is the cause. Use rounder contrasts so as to give the highlights a full exposure. The light which models the subject should be sufficiently concentrated. Do not use too diffused a light on the subject, or relieve the shadows by a side reflector. Use the reflector more from the front, if at all.
Frilling And Softening Of The Film. Keep developer under 75 Fahr., and baths and washing water as near that temperature as possible. Any large difference in the temperature of these solutions will cause frilling in any kind of weather. Use ice to keep the developing solution at proper temperature. If ice is not at hand use more water in developer. Use fresh, quick working baths or the acid hardening bath. Fix longer and wash less. Plates should be thoroughly fixed and then washing fifteen minutes in running water will be sufficient
Weakness Of Image. Due to under-development, caused by too cold or to weak developer. Developer should be 70 degrees Fahr. in temperature and contain 2 1/2 to 3 grains of pyro to the ounce of developer. After development the developer (pyro) should be clear red and not a dirty brown.
Slowness Of Development. Caused by cold or weak developer or under-exposure. Often a smoky lens or dirty skylight causes the under-exposure. It should be pointed out that developers made with Seeds Sodas develop more slowly, but their action is more uniform and the negatives are clearer and brighter.
749. Too Much Contrast is generally caused by harsh, unnatural lighting of the subject. If the plate is under-exposed, too much contrast frequently results from carrying on the highlights to too great density in hope of bringing out more detail in the shadows. The best results in under-exposure are obtained by stopping development before the highlights come to the limits of printing density.
Fog. Fogged negatives are frequently caused by an unsuitable developing light. Prolonged or forced development, allowed in hopes of getting more density than the exposure and lighting should give, veils the shadows. Too much alkali or too warm developer also cause fog. Use normal developer at a temperature of 70 degrees Fahr. Leaky cameras or plate holders cause foggy or light struck negatives. The little shutter in the plate holder may not close after the slide is drawn. Avoid the possibilities of these troubles by making a habit of covering the camera and plate holder with the dark focusing cloth during drawing of slide and exposure of plate.
751. Our Demonstrators frequently find that light enters the camera where the bellows are attached to the back part of the camera, between the back board and carriage for holder and between holder and carriage. This defect has so often been found to be the cause of flat, weak, foggy negatives, that we give the following directions to discover it. Take the camera out into strong light, take out lens and facing the light place head in camera until the forehead touches the back of the plate holder. Remain in this position until the eyes become accustomed to the absence of light, for until then the leak would not probably be seen.