Additive Color

Additive color describes the situation where color is created by mixing the visible light emitted from differently colored light sources. This is in contrast to subtractive colors where light is removed from various part of the visible spectrum to create colors. Computer monitors and televisions are the most common form of additive light, while subtractive color is used in paints and pigments and color filters. The additive reproduction process usually uses red, green and blue light to produce the other colors. Combining one of these additive primary colors with another in equal amounts produces the additive secondary colors cyan, magenta, and yellow. The colored pixels in displays do not overlap on the screen, but when viewed from a sufficient distance, the light from the pixels diffuses to overlap on the retina. Another common use of additive light is the projected light used in theatrical lighting, such as plays, concerts, circus shows, and night clubs. Every possible combination of luminosities of each light (color) is equal to the full gamut of those three lights (colors).

Results obtained when mixing additive colors are often counterintuitive for people accustomed to the more everyday subtractive color system of pigments, dyes, inks and other substances which present color to the eye by reflection rather than emission. For example, in subtractive color systems green is a combination of yellow and blue; in additive color, red + green = yellow and no simple combination will yield green. Additive color is a result of the way the eye detects color, and is not a property of light. There is a vast difference between yellow light, with a wavelength of approximately 580 nm, and a mixture of red and green light. However, both stimulate our eyes in a similar manner, so we do not detect that difference. (see eye (cytology), color vision.)