The New Student's Reference Work/Pigments
Pig′ments, the color materials of painting. It is necessary to distinguish these from dyeing colors. Pigments are insoluble, and, mixed in oil or water or other liquid, are used for painting. Dye-stuffs are held in solution as tinctorial substances. A pigment must have covering power, that is, it must cover and conceal with an opaque covering the surface on which it is spread. When dry, it must have durability; must resist the air. It should also dry quickly. Pigments for artistic work need to be prepared with more care and of better material, if possible, than pigments for mechanical purposes. A house can be repainted, but a madonna cannot be. Artists' pigments are ground to a finer powder than ordinary paints.