Distemper

Distemper (Fr. détrempe, from détremper, 'to moisten'; Ital. tempera), a method of painting in which opaque colours are mixed with water and such glutinous substances as size, white of egg, the sap of the fig-tree, &c., and applied to a smooth surface of dry plaster or gesso, spread commonly upon wood, but sometimes upon canvas. It is a process of great antiquity; and it was the ordinary method by which the early Italian and Flemish painters produced their easel-pictures (see PAINTING). Such works, when they have been afterwards oiled or treated with an oil-varnish, are frequently difficult to distinguish from oil-pictures. It is to be distinguished from Fresco (q.v.), in which the colours are applied to a fresh damp surface of plaster, with which they become incorporated. Distemper is now most commonly employed for scene-painting.