The art of painting in water colours, as practised by the ancients, in contradistinction to the more modern art of painting in oil. Before John Van Eyck (better known by the name of John of Bruges) found out the art of painting in oil, the painters all painted in water or fresco, on their walls, on wooden boards, and elsewhere. When they made use of boards, they usually glued a fine linen cloth over them, to prevent their opening; then laid on a ground of white; lastly, they mixed up their colours with water and size, or with water and yolks of eggs, well beaten with the branches of a fig-tree, the juice whereof thus mixed with the eggs; and with this mixture they painted their pictures. In limning, all pigments are suitable, except the white of lime, which is only used in fresco. The azure or ultramarine is always mixed with size or gum; and two layers of hot size are always applied to the boards, before the size colours are laid on; the colours are all ground in water, and in working diluted with size water.

When the piece is finished, they go over it with the white of an egg well beaten; and then with varnish, if required.