Which Colors Are Primary?
7 comments
·August 6, 2025chowells
Hobadee
In addition to this, there will always be 2 sets of "primary" colors for a given eye: Additive and Subtractive.
Additive primary colors are necessary when you have no light, and need to create color. Think a black screen, and you are creating colors with RGB pixels.
Subtractive primary colors are necessary when you have full-spectrum (white) light and need to filter down to a single color.
Other "primary" colors, such as the red, blue, yellow pigment primaries we learned in Kindergarten exist because pigments historical couldn't be created perfectly, and those "primaries" are the best way of getting the most colors, but still have a very limited (by comparison) gamut.
kens
Related is that English has 11 basic color terms: black, white, red, green, yellow, blue, brown, orange, pink, purple, and gray. As a result, trying to teach cyan and magenta as primary colors will be much harder than teaching blue and red as primary colors.
For more on basic color terms: https://en.wikipedia.org/wiki/Color_term#Basic_color_terms
adrian_b
While you are right, "magenta" is just a fancy synonym for "purple". It might have been chosen instead of "purple" because the traditional word could be applied to colors having various proportions of red and blue, while "magenta" is intended to convey that the amounts of red and blue are equal. However all the traditional color names, like "red", "green" or "blue" refer to wide ranges of hues, not to a precise hue, so there was really no good reason for the use of the word "magenta".
"Cyan" is a very bad word choice caused by confusions in the translations of Ancient Greek texts made by philologists ignorant of chemistry and mineralogy. In Ancient Greek, "cyan" meant pure blue, not blue-green. More precisely, it was the color of the ultramarine blue pigment, the most expensive blue pigment at that time, which was imported from the present territory of Afghanistan and for which the name "ku-wa-no" was already used by the Hittites, a millennium before the Greeks. Nowadays ultramarine blue is still used as a pigment, but it is made synthetically, so its cost is a small fraction of what it was before the 19th century.
Before the use of "cyan" has started, the color name "blue-green" had been used for a very long time. Similarly, "orange" is a relatively new English word, but the color had been mentioned for many centuries, as "red-yellow" or "yellow-red".
So the awareness of distinct hues is not necessarily limited to the set of simple color words, because most languages have used compound words to name the hues for which they did not have a simple word.
dehrmann
You don't think 5-year-olds can learn two new fancy colors?
No mention that both sets of primaries come from the biology of the average human eye, and other animals might be better served by other colors? Ok, yeah, that's not really relevant to the point the article was actually getting to, but I think it's important to remember. There's nothing magical about those colors. They effectively stimulate color receptors in our eyes such that our brains interpret the input in ways that can be combined to cover a pretty large gamut of the full range our eyes can perceive.
But as for what the article actually does focus on, I absolutely agree. You can create some really striking art by restricting your gamut to the range you can cover with a particular set of pigments.