This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
The plan generally followed is that of coating the hats with a solution of varnish in which a suitable aniline dye has dissolved. The following preparations are in use:
For dark varnishes prepare a basis consisting of orange shellac, 900 parts; sandarac, 225 parts; Manila copal, 225 parts; castor oil, 55 parts; and wood-spirit, 9,000 parts. To color, add to the foregoing amount alcohol-soluble, coal-tar dyes as follows: Black, 55 parts of soluble ivory-black (modified by blue or green). Olive-brown, 15 parts of brilliant-green, 55 parts of Bismarck brown R, 8 parts of spirit blue. Olive-green, 28 parts of brilliant-green, 28 parts of Bismarck-brown R. Walnut, 55 parts of Bismarck-brown R, 15 parts of nigrosin. Mahogany, 28 parts of Bismarck-brown R, which may be deepened by a little nigrosin.
For light colors prepare a varnish as follows: Sandarac, 1,350 parts; elemi, 450 parts; rosin, 450 parts; castor oil, 110 parts; wood-spirit, 9,000 parts. For this amount use dyes as follows: Gold, 55 parts of chrysoidin, 55 parts of aniline-yellow. Light green, 55 parts of brilliant-green, 7 parts of aniline-yellow. Blue, 55 parts of spirit blue. Deep blue, 55 parts of spirit blue, 55 parts of indulin. Violet, 28 parts of methyl-violet, 3B. Crimson, 55 parts of safranin. Chestnut, 55. parts of safranin, 15 parts of indulin.
Shellac........ . . . 4 ounces
Sandarac......... 1 ounce
Gum thus........ 1 ounce
Methyl spirit...... 1 pint
In this dissolve aniline dyes of the requisite color, and apply. For white straw, white shellac must be used.
Use the common solvents, as carbon bisulphide, benzine, wood alcohol, turpentine, and so forth, reclaiming the spirit and shellac by a suitable still.