Colours that are opposite each other on the colour wheel are called complementary colours. When mixed together, each complementary reduces the saturation of the other towards grey; in other words, they desaturate each other. The term desaturation thus refers to the loss of luminosity as a result of the admixture of the complementary colour. In contrast, when placed side by side, complementary colours make each other appear brighter. The contrast between them is one of the strongest and is marked by a sense of oppositeness as well as unity.
