Colour is that property in bodies which, when acted upon by light, impresses the mind, through the agency of our sight, with those sensations which we denominate colour. The light of the sun, which seems perfectly homogeneal and white, is universally acknowledged to be composed of no fewer than seven different colours, viz. red, orange, yellow, green, blue, purple, and violet. A body which appears to be of a red colour has the property of reflecting the red rays more powerfully than any of the others, and so of the orange, yellow, green, etc. A body which is of a black colour, instead of reflecting, absorbs all or the greatest part of the rays that fall upon it; and, on the contrary, a body which appears to be white reflects the greatest part of the rays indiscriminately, without separating the one from the other. See Painting and Pigments.