Created by the reactions of the human eye to certain properties possessed by an object when it reflects or emits light. More technically, colour is determined by ocular interpretation of electromagnetic waves. When the full range of the detectable spectrum is present the colour white is produced; all other colours—red, blue, yellow, etc.—are the result of the omission of the wavelengths specific to that particular colour. In art, the substances used to produce coloured paint can be naturally occurring—vegetable or animal dyes, or minerals—or they can be synthesized chemically. The three primary colours, i.e. those which cannot be created by mixing colours, are red, blue, and yellow; secondary colours, such as green, are obtained by mixing primary colours (in this instance blue and yellow). See complementary colours.