MY Teams Rumble: RGB vs CMYK

Any proper exploration of color has to start with “He Who is the Patron Saint of All Things Color” – Roy G. Biv. Better known in physics circles as the mnemonic device to remember the order of colors in the light spectrum: red, orange, yellow, green, blue, indigo, and violet. Some would argue that the inclusion of indigo is specious, and there only because (this being an American name) we needed to have a vowel there rather than a string of consonants.

Every elementary student learns (or at least used to learn) that the primary colors are red, blue, and yellow. You mix red + blue = purple (violet), red + yellow = orange, and blue + yellow = green. Mix them all together and you get black.

And that’s where things go horribly wrong.

And without Newton’s work, we might not have this iconic album cover

Modern color theory begins back with Sir Isaac Newton’s work with light and prisms. Light when cast through a prism is broken down into our familiar Roy G. Biv pattern, and Newton was the first to experiment with light and color. It was his color wheel that named blue, yellow, and red as primarily colors from which all other colors come from. When you stick needles in your eye to observe color, folks will cut you a bit of slack, I suppose.

However, there are a couple of flaws in his (and subsequent scientists’) theories of primary colors. And the primary problem was that Newton was considering all colors as having equal amounts of space in between them. He was also making color separation analogous to a musical octave of 7 notes with the 8th being the same note as the first. However, there IS no equal spacing in color or sound.

And so, red, blue, and yellow were mistakenly cast as primary colors.

And here the path divides.

Newton and other scientists were working with the color spectrum of light whilst they and other folks involved with color (like artists) tried translating it into pigment. The systems are completely different and while there’s some overlap, they are certainly not the same.

Within the light system of color, the primary colors are red, GREEN, and blue. Light is an “additive” system of color where the absence of color is black and the presence of all color is white. (which brings us right back to Newton and the prism). Green + red=yellow, green + blue = cyan, and blue + red=magenta. (remember those secondary colors, as they’ll be important later). Those three colors create millions of other colors. BUT…only in light. Or light-emitting devices like television, digital movies, and computers. This color system is referred to by its color initials: RGB.

Back over on the pigment side of the color wheel things are rather different. The actual primary colors in regards to pigment are cyan, magenta, and yellow and it is a “subtractive” system. What the heck does that mean?

When we look at an object we perceive its color as the colors of the light spectrum that are not absorbed by the object, but reflected back to us. So, a blue object absorbs (subtracts) all light except that blue and reflects the blue back to our eyes. Hence, it’s “blue.” Cyan + yellow = green, yellow + magenta = red/orange, and magenta + cyan = blue/violet. It’s almost like the familiar color wheel we learned back in grade school. However, mix all the colors together and you sort of get black. But not the perfect pitch black one thinks of as black. To get that color, you have to use … black pigment. This color system is referred to as CMYK from the initials of the first three colors, and then K for blacK. (another B would be quite confusing). This is the color system used by printers and painters – anything involving pigment is a CMYK space. Something else to note: the colors that are in between the CMYK colors just happen to be those in the RGB color space.

RGB and CMYK primaries. the OOs and FFs are part of each color’s hexidecimal code – the color language of the internet. We’ll look at that some other time.

However, the number of colors available within the CMYK system is far less than that within the RGB system (primarily within the purple/violet/magenta range. This is why colors on screen look so much more vivid. They are not only coming from a light-emitting source, there are more colors available in the RGB system. Colors that can only be reproduced in one way within the CMYK universe. But that’s another post. But this is also why Newton’s contemporaries had a difficult time demonstrating and working with color relationships in regards to mixing colors.


The analogy that I always give people about these two color systems is referring back to one of my favorite childhood items: crayons. Working in the CMYK color space, one is figuratively coloring with the set of 96 crayons. However, RGB is coloring with the set of 152 colors, so its creations can have a much wider “gamut” of colors.

This Peacock Mantis Shrimp commands you to go listen to the podcast.

Next: we take a look at conversion experiences, and talk about where those bright print colors come from, and what a good designer knows about color. And once again, I’ve written a post along the lines of a paper, but this is the foundation of all color work and there’s some interesting history there. Want to listen to one of the best explanations of color gamuts and how various animals (and insects) see colors. Listen to this podcast over on RadioLab. It’s one of my all time favorites (and lots of other folks!) was recently updated.


In closing: surely I can’t be the only graphic designer out there who, upon hearing about the movie on Supreme Court Justice Ruth Bader Ginsberg, thought “RGB? They’re making a movie about color? COOL!”

Posted in Color