Color Theory: Q & A Part 6 - Primary Colors

This is a continuation of the Color Theory: Q & A generated by my first Color Theory post.
Q: What are the primary colors?
A: The term "primary colors" refers to the theoretical fundamental, basic, or "parent" hues, from which all colors can be created by mixing.

In elementary art class I was taught that red, blue, and yellow are the true primary colors. Then in physics and film studies I was taught that magenta, yellow, and cyan were the primary colors (Wikipedia covers color motion picture film better than I can handle without traumatic flashbacks). I am apparently, not the only one confused. Over the years, there have been several theories concerning the true primary hues. Some theories propose four primary colors; many have three. Harald Kueppers' color system has six primaries: red, blue, yellow, green, magenta, and cyan.

Discussions of the true primary hues can lead to confusion because the hues from which all colors can be created depend on the medium or the substance that is being mixed. The primary hues in mixing light (like in film and physics) differ from those of paints (like in art class); the primaries for mixing transparent paint and dyes (like the inks used in the Pantone system) differ from those of opaque or heavily applied paints (like those used in the Munsell system).

Traditional printing processes employ magenta, yellow, cyan, and black transparent inks to print full-color images. Magenta, yellow, and cyan thus earned then name "the process colors." Home color printers usually use the process colors plus black inks. To extend the gamut of colors contemporary printers often use the process colors, black, and red, blue, and green ink.

Mixing oil and acrylic paints requires two sets of red, blue, and yellow primaries: a "cool" set and a "warm" set. I don't really understand this and will supplement this answer once I get through the rest of the text in The New Munsell Student Color Set.

In Daren Pitts Redman's dyeing class we mixed dry red dye with dry blue dye to make our purple dye, red and yellow for orange, and blue and yellow for green. She mentioned that some fabric dyers don't like the results of their primary mixing, particularly in the green range. So they'll mix their own oranges and purples, but buy a commercially produced green, which probably uses a green pigment instead of mixing yellow pigment with blue pigment. Until recently, I thought the Fiber Reactive Procion Dyes dyes available from Dharma Trading Co. were pure single pigment, not mixtures of primaries. But if you read the Dharma Trading Co. catalog they warn that all the dyes labeled with a "T" contain #25 Turquoise, and therefore require the same special care required by #25 Turquoise. So some of the dyes you can purchase are not a single pigment, but a mix of pigments. Huh. I'm going to have to look into this dyeing stuff.

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