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.
Temperature Of Developer. The temperature of developer has considerable influence on its action. As a general rule from 60° to 65° is best. Above this, surface action becomes too rapid, and is therefore apt to produce flatness and fog before the lower layers of film are sufficiently penetrated and acted on to produce the required density and contrast. Very cold developer, on the other hand, gives clear negatives, but they are likely to be insufficiently developed, as cold developers act very slowly, giving the impression that the plate is at fault, and leading one to complain to the plate-maker, which would have been unnecessary had the temperature been raised a little. Temper the developer with a little hot water in winter and a little ice in summer.
Suggestions For The Beginner. On developing, pour the developer over the plate by running the graduate along the side of the dish so as to propel a wave of the solution across the plate and avoid patches and streaks caused by quick acting developers when they are not properly applied.
Patches of fog may come from fingers or thumb that are contaminated with hypo. Keep every trace of hypo out of the developer and off the plates until after development is complete and the plate rinsed.
Drying The Negatives. Plates are best dried in a moderately warm room, the temperature of which should not vary much, with good ventilation. They should not be placed too close together. A plate must never be laid in the sunlight to dry, as this may melt the film, cause transparent holes, and, if nothing worse, will increase the intensity. In cold weather do not allow the negative to get too cold while drying; this not only retards the drying, but in case the moisture therein should freeze, it would cause mottled spots. If the negative is partly dry and then removed to another room which is much warmer or colder, it will cause a difference in the density of the part to dry last. If a negative is wanted in a hurry, it may be quickly dried by laying it for ten minutes (after thoroughly washing) in a bath of alcohol, when it will dry rapidly. If dried in this way the negative must first be very thoroughly washed, for if any hypo be left in the film an insoluble white deposit may be formed, which cannot afterwards be removed.
295. If a plate, after being in the hypo, is only rinsed and allowed to stand exposed to the air for some time, it will lose intensity to a considerable degree. After thorough fixing, then thoroughly wash the negative.
296. Three Good Rules which will greatly help to insure clean work:
No. 1. Always keep hypo by itself; mix it only in its own dishes, and always wash your hands before touching anything else.
No. 3. Keep your workroom clean.