Because every other colour absorbs at least one specific wavelength, no other colour combination can be used to create white paint. Subtractive colour mixing is the process of combining paints or filters to create new hues.
For instance, cyan paint, regardless of its hue, absorbs some red-wavelength light. Yellow paint absorbs some blue light. The mixture partially absorbs both red and blue wavelengths, resulting in a green hue. Magenta pigments absorb some green light, so mixing equal amounts of equally bright cyan, yellow, and magenta paint produces grey. Even if all three pigments are very light, the only possible result is a very light grey because not all wavelengths are reflected rather than absorbed. Therefore, the only way to produce pure white paint is to use a single compound that reflects red, green, and blue light, which appears white to the human eye.
In additive colour mixing, however, wavelengths are emitted rather than absorbed. When red, green, and blue lights converge on the same spot, the result is white. This principle is utilised in televisions, fluorescent lamps, and computer monitors.
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