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.
Grayish Mottled Or Granulated Appearance Of Edges Or Entire Print. This is due to under-exposure and forced development; old paper; paper kept in a damp place; moisture; chemical stains; fumes from ammonia, turpentine, illuminating or coal gas. Always keep the paper in a dry, cool place, give full exposure and never force development.
Prints Too Black. This is generally caused by printing from negatives that are too weak, or thin; by over-exposure or over-development; insufficient amount of bromide of potassium in the developer. Perhaps you have selected the wrong grade of paper to use. Try the " Regular " paper in place of the " Special," as more contrast will thus be secured. Or, if you have too much contrast try the "Special;" this will give you more softness.
Green Tones. Green tones are generally caused by using too much bromide; over-exposing; using a developer too weak or old. Use a more concentrated developer or add less bromide. A strong, fresh developer permits the use of more bromide than a weak one, without producing greenish blacks.
Grayish Whites. If there is not enough bromide in the developer, the whites will turn gray. Add a few more drops of a 10% solution of bromide. If the print is under-printed and forced in development, it will cause grayish whites. Using old paper will cause grayish whites, or it is also possible that the paper has been fogged by white light while printing or during developing.
Brownish Blacks. If the developer has become old and discolored, or too warm, you are likely to produce brownish blacks. Developer exposed to the air will oxidize and then produce brownish blacks. This is also caused by using developer too weak. This may also be due to over-exposure, an excessive amount of bromide, or an old or incorrectly compounded developer. Never use developer after it has become discolored or muddy to any great extent. Imperfect fixing; fixing bath lacking sufficient acid; and if prints are not kept moving to allow even fixing, are all causes for brown or light stains. If the brown tone appears after immersing in the fixing bath, it may be traced to impure sulphite of sodium, or too warm a fixing bath.
Too Much Contrast. If your negative is a strong and contrasty one, use " Special" paper and develop with full strength developer. A diluted developer will give more contrast. Double strength developer will produce softness. When double strength developer is used increase the exposure and use more bromide to keep the print clear in the highlights. This will give more softness. (See Special Manipulation of Velox.)