Remember the color wheel?
When you were a kid, your art teacher probably taught you the standard color wheel: If you have red, blue, and yellow paint, you can combine them to make any color (except black, white, gold, silver, magenta, neon anything…) Okay, almost any color. Red + Blue = Purple, Blue + Yellow = Green, and Red + Yellow = Orange. Mix all three, and you get Brown.
But if you’ve ever picked up a standard set of kids’ tempera paints and tried to mix them, you’ve probably noticed that things aren’t quite this simple.
Here are the results of mixing red, blue, and yellow. The green looks pretty good. The orange is still red, and the “purple” is terrible. No, that’s not your monitor messing up. It is actually almost black.
This happens because the red and blue in these kits aren’t actually primary colors. The real primary colors are yellow, cyan, and magenta. Why were we taught that red and blue are primary paint colors in school? I don’t know. I suspect it’s because teachers think little kids understand red and blue but don’t know what “cyan” and “magenta” are, (though if you’ve ever discussed dinosaurs with a four year old, you’ve know that kids know lots of big words).
Thankfully, if you are cursed with red, yellow, and blue, you can improve your results.
The blues that come in standard kids’ paints tend to be very dark, and the reds are dark compared to the yellow. Yellow is, by nature, very light. If you try to mix equal quantities of these pigments, the dark colors will overwhelm the light ones.
Add white to lighten the blues and reds, then increase the amount of yellow in the orange and red in the purple:
Why bother with the white? Even though you are adding paint, paint is essentially subtractive. Paint works by absorbing most of the light that strikes it and only reflecting a few particular wavelengths. When you mix paints, you don’t increase the range of light reflected, but narrow it: you’re now blocking two paints’ worth of colors. This is why our purple looks almost black.
So if you’ve mixed your colors and the result is still too dark, add some white.
The purple is still pretty blah, but purple is hard. We didn’t even invent good, cheap purple paint until the 1800s. (Before then, purple was expensive, which is why it was associated with kings.) Don’t feel bad if you can’t get a good purple and just buy purple paint.
Now let’s talk about brown. Here is the brown I get when I mix all three colors.
Yeah. That’s awful.
I remember being very frustrated as kid because no matter how I mixed my red, blue, and yellow, I just got disgusting colors that didn’t even deserve the name “brown.”
There is a much easier and better way to make brown: add a touch of black to your orange. Yes, the orange. Brown is actually dark orange.
Here you go: orange + black. See? Isn’t that better? Now we’ve got a color that could grace a tasty bar of chocolate, a friendly dog, or a wooden table.
Why is brown dark orange? That’s a good question. I’m not sure, but I think it has to do with how our eyes physically perceive color.
Dark blue and light blue are both good, recognizable colors.
Dark red and light red are both good colors.
Dark green and light green are both good colors.
Dark yellow isn’t a thing. Try it. Mix yellow+black. Now you’ve got olive, not yellow.
And dark orange, as we’ve discussed, is brown.
You might have noticed that when people talk about light, instead of paint, they use a different set of primary colors: blue, red, and green. Yes, blue and red are actually the primary colors of light. Light is additive: if you put more light in, you get more light out. Mix all of the colors of light together and you get white light, like the sun. The sun makes a lot of light.
The cones in your eyes are optimized to detect particular wavelengths of light. They tell your brain what they’ve detected, and your brain constructs an image that you perceive as color. Our cones are optimized to perceive red, green, and blue light.
Yellow light is made by mixing red and green, so when you perceive yellow, both red and green cones are activating at the same time. Orange is the same story, but with a more red activation.
A “dark” version of a color is just a version that is emitting/reflecting less light. I suspect that when you see “dark green,” you are activating fewer of your green receptors, but still activating some of them, so your brain gets a clear signal that says “green.” When you see dark red, the same thing happens. But in order to see yellow and orange, you need to activate both receptors. I suspect that when you see dark yellow and dark orange, not enough of both red and green get activated to send a clear picture to your brain. What you end up with is, essentially, a degraded signal: brown.
You can degrade signals in other ways–by just blocking out a lot of the colors, as when you mix all of the paints, for example–but it’s faster and easier to work with orange. (And that’s definitely the technique you’ll use if you’re coloring on a computer.)
Good luck and happy painting.