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.
Little Blisters Forming On Plate. Blisters on the plate should be treated exactly as you would a frilling plate. These little blisters come from the same source that causes the plate to frill, and if placed in the alum hardening bath immediately after fixing, the blisters will be avoided. Should the blisters appear during fixing in the hypo, then use an acid-fixing bath.
Negatives Fogging During Development. Extremely weak developer and excessively long development under the ruby light is apt to fog the plate; also an excessive use of carbonate and sulphite. To overcome this difficulty extreme care must be exercised in regard to the ruby light, for by long development even the ruby light is apt to fog the plate. You must also be careful and prevent the air from affecting the developer, which deteriorates, and causes oxydization very rapidly. A good plan is to have a cover for the tray, being careful, however, to rock the tray occasionally during development.
Negative Flat. This is generally caused by misjudging the plate in regard to exposure. If, for example, your plate was only slightly under-exposed there would be no strength to the highlights, and the result would be a flat plate. If you find the plate does not gain strength in the highlights, and appears flat, place the plate in normal developer. You may even find it necessary to add a little more of the developing agent (pyro). Over-exposures and under - development will also produce flat negatives. Such plates can be improved by intensifying. (See Chapter V (Purple Tones On Collodion And Gelatin Glossy Papers), on Intensifying.)
Negatives Lack Strength And Snap. When you find that the plate refuses to build up any stronger in a weak developer, transfer it to the normal developer for a minute or two, or until you have produced the proper strength in the highlights.