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.
232. Varying water conditions have considerable to do with the manipulation of printing-out papers. Generally in the spring and fall of the year all printers experience more or less trouble, and in many instances blame is placed on the paper. Occasionally, this is the true cause. However, in the majority of cases the trouble lies in the water used. Water containing vegetable matter, or that which is very much alkaline will cause all kinds of trouble. You will notice that after a heavy fall of rain the water is impregnated with vegetable matter, generally testing quite alkaline. There are instances where even this alkali does not interfere with the toning and the baths seem to tone quite well, yet the prints after mounting dry up brown and yellow.
233. Usually when you are experiencing the most trouble with muddy prints they will tone exceedingly fine in the gold bath, but refuse to tone in the platinum. This is easily accounted for. It is positive proof of very alkaline water, and prints should be handled under such circumstances in exactly the same manner as you find necessary when using very alkaline water. Under such conditions wash the prints in the regular way, but use no added alkali in first nor succeeding washings, for the reason that the water is already alkaline. After the gold toning, wash prints through a citric acid bath of say 10 to 20 drops saturated solution of citric acid to each gallon of water. The acid is used to counteract the excess alkali. Finally wash in two changes of plain water, which will remove all the excess acid and leave the prints neutral. They are then ready for the platinum bath.
234. Prints after leaving the gold bath, being decidedly alkaline and the water alkaline as well, it is impossible to remove all the excess alkali from the prints with this alkaline water. However, it must be done before the prints enter the platinum bath, which is an acid solution. The prints entering this platinum bath in an alkaline condition will soon fill it with alkali, causing the platinum to precipitate. In a short time all the platinum being precipitated to a sediment on the bottom of the tray, the prints would refuse to tone, even after more platinum was added. Should you be successful in forcing a tone in this bath by using a strong platinum solution, beware of yellow, muddy prints after mounting, as they will surely show up sooner or later. To avoid this trouble, whenever you find the platinum bath precipitated and refusing to tone, test your wash water with blue and red litmus paper to see if it is alkaline. If the red litmus paper turns blue almost instantly the water is strongly alkaline. In this case, treat your prints to the acid bath advised above, make up a new platinum bath and start anew, when you will find your path clear of difficulties.
235. After the prints have gone through the platinum solution and are in an acid condition, you must again eliminate the acid by washing in two changes of water, which brings the prints back to a neutral state, as they were at first. The wash water being alkaline, a few changes will do this. Prints must be neutral before being placed in the hypo bath. The first bath must be slightly alkaline, or, at least, neutral, never acid. Should prints enter the hypo bath in an acid condition they would be apt to bleach and give muddy whites.