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.
Negatives Too Strong In Color - Yellow. Either your sulphite of soda solution has deteriorated by becoming old, or it is not strong enough. Sometimes sulphite of soda solution that has been made up for a considerable length of time, while it may test the same strength, has lost the chemical action necessary to prevent the pyro from staining the plate. Discard this sulphite, and make up a new solution. The amateur who only develops occasionally should make up small stock solutions. Both sodas should be kept in tightly corked bottles. Yellow color may be removed from negatives by immersing in alum clearing bath. See formula in Instruction on Reducing.
Testing Old Sulphite Of Soda Solution. Place a small quantity of your pyro solution in your graduate; next add a small quantity of sulphite, then add the same quantity of carbonate. If your developer turns dark, and refuses to clear up, as it should if the sulphite was fresh, you may be certain that the sulphite is too old and deteriorated. In making this test, use the same proportions that you would in preparing your developer for developing.
Negatives Which Appeared Sufficiently Developed, Very Thin After Fixing. If your negative is of a scene with heavy shadows, or a portrait of Rembrandt Lighting, the negative should be thin, and while it may appear too thin you will find that it has sufficient strength for good printing quality. If the highlights of the negative are very thin it may be possible that you are under-developing; therefore, you must experiment. Carry the developing a trifle further, and then watch your resulting prints.
Proper Detail In Shadows. While this is governed greatly by the lighting, the detail in the shadows is often lost in the developing, and in the improper preparation of the developer, or from not handling the negative correctly during development. If you find that the highlights are building up strong, it is possibly due to the fact that your lighting was contrasty, or you under - exposed the plate. It is, therefore, necessary that the strength of the developer should be reduced and this you can do by adding water to the developer, thus treating the plate as under-exposed.
Plate Inclined To Develop Contrasty. This difficulty is generally caused by either contrasty lighting, or under-exposure. Treating the plate for under-exposure during development - weakening the developer - will enable you to produce softer highlights, and, therefore, at the same time build up the shadows, and produce less contrast.
Securing Half - Tones In Highlights. If the lighting is contrasty, even though the plate is fully exposed, the highlights will develop up exactly as they are lighted, and you lose practically all the detail. This is not the fault of the developer, but of the lighting. Subdue your lighting. You can improve a contrasty lighting in the developer by reducing the strength of your developer - adding water. This will give the shadows a chance to build up, and at the same time prevent the highlights from becoming dense, and will enable you to produce detail and half-tones.