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.
Treating Water Which Is Strongly Alkaline Or Acid. It is always advisable, in case you experience trouble in any manipulation, to first look to the water conditions and test thoroughly before investigating elsewhere for the trouble. If you find the water turns red litmus paper blue, even slightly, you will know that the water is alkaline and requires no altering. Should it test strongly alkali, you will require no additional alkali in the gold bath, and can dispense with Stock Solution No. 3 entirely; or at least, use less than the formula calls for. If, on the other hand, you find that the water turns the blue litmus paper red, you will know that the condition of the water is acid. At once take steps to neutralize it, by adding borax solution or carbonate of soda to the water until it neither turns the blue paper red, nor the red paper blue. It is a good plan to use boiled or distilled water in preparing all the chemicals and baths, especially the toning baths.
Muddy And Impure Water. Many cities and sections of the country are continually troubled with " roily " and impure water. Some of these contain sulphates, chlorides, magnesium in different forms, sulphur, iron in various forms, and a large variety of vegetable substances, effects of which are visible especially in the winter and spring months. This difficulty can be overcome in an inexpensive manner.
Purifying The Water. A simple and easy way to purify the water, so far as the impurities which affect the chemicals used in toning are concerned, is to get an empty whiskey or alcohol barrel. Remove the head; clean the barrel thoroughly; place the barrel on a shelf in a corner over your sink, at an elevation sufficient to enable you to draw the water from it. About six inches from the bottom of this barrel bore a hole and fit a faucet. Use a faucet with a threaded screw for hose connection. The advantage of the hose connection is that it will enable you to carry the water to any tray. Fill the barrel with water. Dissolve a table-spoonful of powdered alum in a cup of hot water, and while stirring the water in the barrel gradually pour in the alum water. After a thorough mixing test the water with blue litmus paper. If the water tests acid, or in other words, turns blue litmus paper red, you will have added sufficient of the alum. Allow the water to stand in the barrel over night, or until you wish to use it. You will find the alum will clear the water very nicely and also settle the vegetable matter and other impurities. The sediment which will collect in the bottom of the barrel will do no harm if the barrel is cleansed at least twice a year. Every time you add water to the barrel apply the alum treatment in manner described. Only sufficient alum is required to make the water acid.
245. When using water from this barrel, it being in an acid state will make it necessary to neutralize it before use. This you can do by adding carbonate of soda or borax solution to each tray of water. Test the water by using red litmus paper. Add sufficient of the alkali to turn red litmus paper blue. Where a large quantity of water is used a barrel may be arranged to feed from the top and work automatically. As the water is drawn from the barrel it fills itself and shuts off when the barrel is filled. In this case place a pound of alum crystals in a linen sack and hang it in the barrel, and the water will take up enough of the alum to acidify the water and precipitate the vegetable matter which will collect at the bottom of the barrel. This barrel should be cleansed every few months, for unless this is done you will in time have a collection of mud in the bottom of the barrel, caused by the vegetable matter which the alum has precipitated.
246. It is very seldom that the above treatment of the water is necessary, and unless you are experiencing any difficulty it is needless to go to this trouble. Should you, however, experience any difficulty of this kind, you will know how to treat it.