Carbon Paper. A variety of substances may be used, such as fine soot or ivory black, ultramarine[p. 172] or Paris blue. Mix either with fine grain soap, so it is of a uniform consistency and then apply to the paper with a stiff brush, rubbing it in until it is evenly spread over the surface.
Tracing Paper. Take unsized paper and apply a coat of varnish made of equal parts of Canada balsam and oil of turpentine. To increase the transparency give another coat. The sheets must be well dried before using.
Photography.—Developers.
1. Pure water, 30 ounces; sulphite soda, 5 ounces; carbonate soda, 2 1/2 ounces.
2. Pure water, 24 ounces; oxalic acid, 15 grains; pyrogallic acid, 1 ounce.
To develop use of solution 1, 1 ounce; solution 2, 1/2 ounce; and water, 3 ounces.
Stock solutions for developing: Make solution No. 1 as follows: water, 32 ounces; tolidol, I ounce; sodium sulphate, 1 1/2 ounces.
Solution No. 2: Water, 32 ounces; sodium sulphate.
Solution No. 3: Water, 32 ounces; sodium carbonate, from 4 to 6 ounces.
Fixing bath. Add two ounces of S. P. C. clarifier (acid bisulphate of sodium) solution to one quart of hypo solution 1 in 5.