Page:An Elementary History of Art.djvu/332

304 Painting. In drawings of the quality known by the French as gouache, opaque colours are thickly spread over the draw- ing. They look heavy and massive, but present a favour- able opportunity for the development of pure effects of colouring. By this method, which is extensively practised at Naples and elsewhere on the Continent, though little known in England, glowing effects of colour can be represented with truth and force.. The modern water-colour artists have, many of them, now adopted a slightly altered mode of painting, depending largely upon the employment of opaque colours for its effects. This borders closely on oil painting, and seems wanting in the peculiar softness and transparent depth of colour which are the distinctive property of true water colours. In the middle ages, wood was principally employed as the ground for movable pictures; but, as it was liable to rot and to destruction by worms, it was supplanted in the fifteenth century by canvas, which was first used, it is said, by Rogier van der Weyden, and which is now almost universally preferred. Copper has been not unfrequently used as a ground by painters, and a few pictures have been executed on marble, and even on silver. Before oil painting was adopted, other materials were in use, to which the name of tempera or distemper colours has been given. In tempera-painting the colour is mixed with white of egg, glue or size. A painter's colours are called pigments ; those employed by the ancients appear to have been earths or oxides, mixed with gum or glue instead of oils. Unfortunately, however, colours so obtained are wanting in freshness and soon peel off. They are now only used for scene-painting