in Painting, denotes a lay or impression of colour, whether in oil or water, with which the painter covers the canvass, wall, wainscot, or other matter to be painted. The word is also used for a lay or impression on any thing, to make it firm and consistent, or to screen it from the weather.

Paintings are covered with a couch of varnish. A canvass to be painted must first have two couches of size before the colours be laid; and two or three couches of white lead are laid on wood before the couch of gold be applied. The leather-gilders lay a couch of water and the albumen of eggs on the leather, before they apply the gold or silver leaf.

The gold-wire drawers also use the word couch for the gold or silver leaf with which they cover the mass to be gilded or silvered before they draw it through the iron, which gives it its proper thickness. The gilders use couch for the quantity of gold or silver leaves applied on the metals in gilding or silvering. Each couch of gold is about one leaf, or two at most; and each of silver three. If the gilding be hatched, there are required from eight to twelve couches, and only three or four if it be without hatching. To silver there are required from four to ten couches, according to the beauty of the work.