Editing Red (section)

=== In color theory and on a computer screen ===
In the [[RYB color model]], which is the basis of [[traditional color theory]], red is one of the three [[primary color]]s, along with blue and yellow. Painters in the Renaissance mixed red and blue to make violet:  [[Cennino Cennini]], in his 15th-century manual on painting, wrote, "If you want to make a lovely violet colour, take fine lac ([[Lake pigments#History and art|red lake]]), [[ultramarine blue]] (the same amount of the one as of the other) with a binder"; he noted that it could also be made by mixing blue [[indigo]] and red [[hematite]].<ref>{{Cite book|url=https://archetype.co.uk/our-titles/cennino-cenninis-i-il-libro-dellarte-i/?id=224|title=Cennino Cennini's Il libro dell'arte: a new English translation and commentary with Italian transcription|publisher=Archetype|year=2015|isbn=9781909492288|editor-last=Broecke|editor-first=Lara|location=London|pages=115|oclc=910400601|access-date=2018-11-23|archive-date=2020-11-01|archive-url=https://web.archive.org/web/20201101102156/https://archetype.co.uk/our-titles/cennino-cenninis-i-il-libro-dellarte-i/?id=224|url-status=live}}</ref>

In the CMY and [[CMYK color model|CMYK]] color models, red is a secondary color subtractively mixed from magenta and yellow.{{citation needed|date=January 2023}}

In the [[RGB color model]], red, green and blue are [[additive primary colors]]. Red, green and blue light combined makes white light, and these three colors, combined in different mixtures, can produce nearly any other color. This principle is used to generate colors on such as computer monitors and televisions.  For example, magenta on a computer screen is made by a similar formula to that used by Cennino Cennini in the Renaissance to make violet, but using [[additive color]]s and light instead of pigment:  it is created by combining red and blue light at equal intensity on a black screen. Violet is made on a computer screen in a similar way, but with a greater amount of blue light and less red light.<ref name="huevaluechroma1">{{Cite web|url=http://www.huevaluechroma.com/041.php|title=The Dimensions of Colour: Part 4. Additive Mixing|last=Briggs|first=David|website=huevaluechroma.com|access-date=Nov 23, 2018|archive-url=https://web.archive.org/web/20181113180931/http://www.huevaluechroma.com/041.php|archive-date=November 13, 2018|url-status=live}}</ref>

<gallery mode="packed" heights="150">
File:Boutet 1708 color circles.jpg|In a traditional [[color wheel]] from 1708, red, yellow and blue are primary colors. Red and yellow make orange; red and blue make violet.
File:RGB combination on wall.png|In modern color theory, red, green and blue are the additive primary colors, and together they make white. A combination of red, green and blue light in varying proportions makes all the colors on your computer screen and television screen.
File:RGB pixels.jpg|Tiny red, green and blue [[sub-pixel]]s (enlarged on left side of image) create the colors you see on your computer screen and TV. 
</gallery>