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.
Streaky Prints. These are usually caused by insufficient washing before toning, and sometimes by an acid toning bath; toning too fast, or too many prints at a time; not separating prints while toning. Be careful to see that the prints are picked over and over when washing. See that the bath is slightly alkaline, and if it tones too fast add more water. Never have more prints in your toning bath than you can handle conveniently.
Slow Toning. This is caused by either too weak a toning bath (not using enough gold) or the bath being acid, but more generally caused by insufficient preliminary washing. Still another reason would be using a toning bath too cold. The toning bath should be worked at from 65 to 70 degrees Fahr.
Edges Toning Blue, Center Of Print Toning Even. This will occur if your bath tones too rapidly, if it is strongly alkali, or if the prints are not continually moved while in the toning bath. If the bath tones too rapidly add more water; if too strongly alkali, neutralize by adding water and enough gold, without adding more borax to neutralize the alkali already in the bath. Or, if the bath is much too alkali, a drop of nitric or muriatic acid C. P. added will have the effect of neutralizing it.
Judging When Prints Are Toned. A print is completely toned when it is clear and crisp throughout. You should judge the print by raising it from the bath and looking through it, and not by looking upon it while laying in the bath, as it may look clear upon the surface and not be clear throughout. If by looking through the print it appears clear and brilliant - not muddy and bricky - it is then fully toned. If patches or streaks exist they must be toned out before the print is fully toned. The final color of the print is a matter of individual taste.
Black Spots With Comet-Like Tails. These are found either in the wash waters or toning bath, and are caused by iron rust coming from the water pipe and settling on the surface of the paper. Filter the water and use a little salt in the first wash water.
Pink Whites. These are caused by an acid toning bath. Neutralize by adding a little borax.
Bleaching While Fixing. All prints will grow somewhat lighter in the hypo, but this is not bleaching. When a print bleaches in the hypo, the highlights, or whitest parts of the print, lose in detail - become chalky - and turn a bluish tint with shadows weak and mealy. This is generally caused by the use of an acid hypo bath. Carefully test your hypo with litmus paper, and if you find it is acid, add a little carbonate of soda or borax solution until red litmus paper turns slightly blue in two or three minutes. Always have the hypo bath slightly alkali.