As an excipient for oily inks, a mixture of castor oil and crude oleic acid, in parts varying according to the coloring material used, is admirable. The following are examples:

Black

Oil soluble nigrosin and crude oleic acid in equal parts. Add 7 to 8 parts of castor oil.

Red

Oil soluble aniline red, 2 parts; crude oleic acid, 3 parts; castor oil, from 30 to 60 parts, according to the intensity of color desired.

Red

Dissolve 1/4 ounce of carmine in

2  ounces strong water of ammonia, and add 1 drachm of glycerine and 3/4 ounce dextrin.

Blue

Rub 1 ounce Prussian blue with enough water to make a perfectly smooth paste; then add 1 ounce dextrin, incorporate it well, and finally add sufficient water to bring it to the proper consistency.

Blue

Oil soluble aniline blue, 1 part; crude oleic acid, 2 parts; castor oil, 30 to 32 parts.

Violet

Alcohol, 15 ounces; glycerine, 15 ounces; aniline violet, 2 to 4 drachms. Mix, dissolve, pour the solution on the cushion, and dab on with a brush.