White is an achromatic color, of maximum clarity and null darkness. Perceptually, it is the consequence of the photoreception of an intense light constituted by all the wavelengths of the visible spectrum, by three wavelengths (long, medium and short) or by two complementary wavelengths. It resembles the color of snow, although other substances of maximum reflectance, such as magnesia, gypsum color and barite (barium sulfate), are more specific examples of white.The term “white” includes similar colorations standard white, called whitish or whitish, which have a slight suggestion of saturation and hue.

Source: wikipedia.org