Editing Primary color (section)

{{Short description|Fundamental color in color mixing}}
{{About|colors|other uses|Primary Colors (disambiguation){{!}}Primary Colors}}
{{Use American English|date=October 2020}}
[[File:CRT phosphors.png|right|thumb|upright=1.75|The [[emission spectra]] of the three [[phosphor]]s that define the '''additive primary colors''' of a [[cathode-ray tube|CRT]] color video display. Other electronic color display technologies ([[LCD]], [[Plasma display]], [[OLED]]) have analogous sets of primaries with different emission spectra.]]

'''Primary colors''' are [[colorant]]s or colored [[light]]s that can be mixed in varying amounts to produce a [[gamut]] of [[colors]]. This is the essential method used to create the perception of a broad range of colors in, e.g., electronic displays, color printing, and paintings. Perceptions associated with a given combination of primary colors can be predicted by an appropriate mixing model (e.g., [[additive mixing|additive]], [[subtractive mixing|subtractive]]) that uses the physics of how light interacts with physical media, and ultimately the [[retina]] to be able to accurately display the intended colors. 

The most common color mixing models are the additive primary colors (red, green, blue) and the subtractive primary colors (cyan, magenta, yellow). Red, yellow and blue are also [[#Red, yellow, and blue as primary colors|commonly taught as primary colors]] (usually in the context of subtractive color mixing as opposed to additive color mixing), despite some criticism due to its lack of scientific basis.

Primary colors can also be conceptual (not necessarily real), either as additive mathematical elements of a [[color space]] or as irreducible phenomenological categories in domains such as psychology and [[Philosophy of color|philosophy]]. Color space primaries are precisely defined and empirically rooted in [[psychophysics|psychophysical]] [[colorimetry]] experiments which are foundational for understanding [[color vision]]. Primaries of some color spaces are ''complete'' (that is, all visible colors are described in terms of their primaries weighted by nonnegative primary intensity coefficients) but necessarily ''imaginary''<ref name="handprintprimaries">Bruce MacEvoy.  "Do 'Primary' Colors Exist?" ([http://www.handprint.com/HP/WCL/color6.html#imaginary imaginary or imperfect primaries section] {{Webarchive|url=https://web.archive.org/web/20080717034228/http://www.handprint.com/HP/WCL/color6.html#imaginary |date=17 July 2008 }}).  ''Handprint''.  Accessed 10 August 2007.</ref> (that is, there is no plausible way that those primary colors could be represented physically, or perceived). Phenomenological accounts of primary colors, such as the psychological primaries, have been used as the conceptual basis for practical color applications even though they are not a quantitative description in and of themselves.

[[set (mathematics)|Sets]] of color space primaries are generally ''arbitrary'', in the sense that there is no one set of primaries that can be considered the canonical set. Primary pigments or light sources are selected for a given application on the basis of subjective preferences as well as practical factors such as cost, stability, availability etc.

The concept of primary colors has a long, complex history. The choice of primary colors has changed over time in different domains that study color. Descriptions of primary colors come from areas including philosophy, art history, color order systems, and scientific work involving the physics of light and perception of color.

Art education materials commonly use red, yellow, and blue as primary colors, sometimes suggesting that they can mix all colors. No set of real colorants or lights can mix all possible colors, however. In other domains, the three primary colors are typically red, green and blue, which are more closely aligned to the sensitivities of the [[photopigment|photoreceptor pigments]] in the [[cone cell]]s.<ref>[https://science.howstuffworks.com/primary-colors.htm Primary Colors Are Red, Yellow and Blue, Right? Well, Not Exactly], ''HowStuffWorks''</ref><ref>[https://www.olympus-lifescience.com/en/microscope-resource/primer/lightandcolor/primarycolorsintro/ Introduction to the Primary Colors], ''Olympus Life Science''</ref>