When I was a kid, I was taught in art class that the primary colors were red, yellow, and blue. Typically, this was taught as a kind of fire engine red, banana yellow, and recycling-bin blue.
I was also taught that the secondary colors, which can each be mixed from two of the primaries, are green, orange, and violet.
- Yellow + Blue = Green
- Red + Yellow = Orange
- Red + Blue = Violet
Note that I didn’t actually use the “primary” colors above to mix the illustration: I used pigments that I knew would do a better job at making those particular colors.
That’s because the secondaries actually mixed from my yellow, red, and blue look like this.
It’s not until adulthood and getting interested in watercolor that it occurred to me to wonder about those childhood lessons, and I’ve since come to embrace the idea that a better set of primary colors are magenta, yellow, and cyan.
The “Modern Primaries” or “CMY Primaries”, as cyan/magenta/yellow are called, just make more sense to me. They work from various points of view:
- Theoretical: My ideas about this were cemented by researching my Science of Color post, which contains diagrams showing how, in additive color mixing (color mixing with light), each of these “modern primary” colors is the overlap between two of the primary colors of light: red, green, and blue.
- Pragmatic: CMYK (cyan, magenta, yellow, and black) are the ink colors that have been used at a large scale in commercial printing for the last century. They sure seem to get plenty of photorealistic variety from just those ink colors.
- Personal: In practice, I personally find it easier to mix a wide gamut of bright colors from paints in these hues than from paints in the traditional primary hues.
But if the primary colors are different from what I was taught, are the secondaries also? What are the secondaries for magenta, yellow, and cyan?
Options
Theoretical Answer: Red, Green, Blue
Since the colors cyan, yellow, and magenta arose from overlaps between the three primary colors of the light in additive color mixing, it makes sense that we’d get back to those same colors by overlapping two each of the three primary colors of paint in subtractive color mixing.
I have certainly found that it is possible to mix red, green, and blue from the “modern primaries.” But straightforward, traditional-primary-style, fire-engine red and recycling-bin blue are actually pretty difficult to mix, in part because they require very unbalanced proportions of the component colors:
- A traditional primary blue is mostly cyan with just a tiny touch of magenta.
- A traditional primary red is mostly magenta with just a tiny touch of yellow.
Placing blue halfway between cyan and magenta, or red halfway between magenta and yellow, can make the color wheel look imbalanced, as Jess Greenleaf found in a great post about the modern primaries with example color “wheels” (triangles).
Balanced Answer: Orange, Green, Violet
What happens when you do mix roughly even proportions of each pair?
Here’s my finding:
- Magenta + Cyan = Violet
- Magenta + Yellow = Orange
- Yellow + Cyan = Green
Look familiar? These are our original, traditional secondaries!
When we use balanced mixes, the resulting color wheel looks better-spaced-out visually. This is where Jess Greenleaf landed on this question, and for this reason.
Actually, the modern primaries is that they do a much better job of mixing these traditional secondary colors than do the traditional primaries.
Complementary Answer: Red-Orange, Green, Blue-Violet
As we’ve seen, you can mix the primaries in various proportions and get different answers. But the secondary colors aren’t just important because they are mixes of the primaries. They can also be seen as complements; they are mixes of two primaries such that, if you add in the third primary, you get gray/black. This leads us to back into the secondaries by identifying the complement of each primary. I turned to my post, Mixing Gray & Black in Watercolor, to find bright complements for the paints I used in my modern primary trio.
A great bright mixing complement for my cyan, Phthalo Blue Green Shade (PB15:3), is Pyrrol Scarlet (PR255).
My magenta, Quin Magenta (PR122), is well complemented by Phthalo Green Yellow Shade (PG36).
I find yellow tricky to complement. The closest might be something like Ultramarine Violet, a very bluish violet.
So, we’ve got red-orange/scarlet, green, and blue-violet! This is also where Bruce MacEvoy seems to have landed in his “secondary palette.”
This set of colors also has the benefit of making the color wheel reasonable and aligning each color across from its complement.
Conclusion
The final option is the one that I like the best, but I think they are all reasonable answers! The more I look into what constitutes the correct spacing to designate a ‘true’ secondary color, the more squishy the idea becomes.
This confusion is also why I don’t like to use the term “tertiary colors.” Typically, the term is used to mean intermediate colors in-between the primary and secondary colors. But since the placement of secondary colors is already squishy and imprecise, I think designating different balances of these mixes as “tertiary” becomes unnecessarily and unhelpfully over-specific. (Besides, some people use the term “tertiary” differently – to mean a mix of all three primary colors. A term without a consistent definition is not useful.)
When I look into these concepts, I try to determine what is the level of detail that is actually useful. I think what is useful to me is thinking of “secondary colors” as those that can be mixed by two primaries, regardless of in what proportion. In that sense, I consider red, red-orange, and orange all to be secondary colors, since they are all mixable by magenta + yellow. Same for blue, blue-violet, and violet, which are all mixable by magenta + cyan. When it comes to placement on the color wheel, I think it is best to arrange them so that complements are across from each other, since this is a major use case of the color wheel.