If I were to ask you what the three primary colors were, you would say “red, yellow, and blue” without even thinking. And you would be 100% correct. But if you instead responded with “red, green, and blue,” you would also be 100% correct.
Yes, you read that right. See, there are two branches of color theory: additive and subtractive.
| SUBTRACTIVE COLOR THEORY | ADDITIVE COLOR THEORY |
|---|---|
| The full spectrum of light hits an object. The object absorbs certain wavelengths, and reflects the rest. Our eyes perceive only the colors that got reflected. It’s called “subtractive” because the color we see is calculated as:
|
One or more sources of colored light are emitted directly from a light source into the eye. The color we perceive is the combination of the different wavelengths of light that hit our eye. It’s called “additive” because the color we see is calculated as:
|
So when you were mixing finger paints to go on your mother’s refrigerator in kindergarten, you were learning that blue + yellow = green. That’s true, but only in subtractive theory, whose primary colors are in fact red, yellow, and blue. In additive theory, the primary colors are red, green, and blue, which are the only three colors you’re actually looking at right now if you’re reading this on a computer screen.
This is an extremely close-up shot of the iPad’s Retina Display. Or microscopic Christmas lights.
So if red, green, and blue are the primary colors in additive color theory, what are the secondary colors? I’m glad you asked. Well, green and blue make cyan, blue and red make magenta, and red and green make yellow. Yes, you read that right too: red and green make yellow in additive color theory. Don’t believe me? Watch this.
See? Told you. You should listen to me. I know stuff. So there you have it. There are two completely different ways to mix colors. One is based on red, blue, and yellow, while the other is based on red, green, and blue (if you haven’t made the connection by now, that’s what RGB stands for).
Congratulations, NeverNoobs. Now you can go around saying that red, green, and blue are the three primary colors, and you won’t be wrong, even though 99% of people will try to correct you anyway.
, just happens to be a professional cinematographer, and provided this explanation:
RGB is used for displays, and CMYK is used for printing. RGB has a greater range of digital colors that can’t be produced verbatim organically (i.e. on paper). The ‘K’ is the black cartridge, which adds black ink to compensate for CMY, which don’t yield a true black. All digital color schemes (RGB, CMYK, YUV/YPbPr, HSL, etc.) are just different expressions of a color, like different ways to express an algebraic equation by isolating variables. CMYK is best for printing because it has the most variables, thus each variable (i.e. color) can be manufactured as an individual ink cartridge, not to mention it can reduce out-of-range colors into printable colors.
So there you have it. Thanks, Jordan!
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