in Painting, is when a design, drawn with a pen or crayon, has some one colour laid over it with a pencil, as Indian ink, bistre, or the like, to make it appear the more natural, by adding the shadow of prominences, apertures, &c. and by imitating the particular matters whereof the thing is supposed to consist.

Thus a pale red is employed to imitate brick and tile; a pale Indian blue, to imitate water and slate; green, for trees and meadows; saffron or French berries, for gold or brass; and several colours for marbles.