Color Theory: Lesson 1: Subtractive Color / CMYK

by Sarah Sammis

The traditional arts, such as painting, uses a subtractive color wheel with the primary colors being cyan, magenta and yellow. If you have a graphics program like Photoshop or Illustrator, you'll see this color scheme listed as CMYK (the K standing for black). As subtractive colors are mixed together, they eventually result in black (in practice, it's actually a very dark gray or dark brown). In printing, black is added to control the the tonality of shades instead of relying on mixing cyan, magenta and yellow together. White, in the subtractive system is represented or created by an absence of color. So a pinkish color, would be only 50% magenta (0% cyan and 0% yellow and 0% black).

The basic color wheel is made up of three triads of colors, the primary colors, the secondary colors and finally, the tertiary colors.

 

Click on the image to see
a larger version

Primary colors:

  • Cyan
  • Magenta
  • Yellow

Secondary colors:

  • Indigo*
  • Red
  • Green

 

Tertiary colors:

  • Blue
  • Purple**
  • Rose
  • Orange**
  • Lime
  • Aqua

 
  * If you look at color balance in Photoshop, it will list blue as a secondary color. As a good deal of color sense is psychological, YMMV. ** In school you might have learned that the primary colors are red, yellow and blue. Under this scheme, orange (made from mixing yellow and red) would be a secondary color as would purple (made rom red and blue). Again, YMMV.


Of course you can continue to mix colors next to each other on the color wheel to get even more gradiations between colors. I highly recommend it.

In the subtractive color scheme, as colors are mixed together, they should eventually result in black. However, you won't get a solid black from mixing all your colors together.

Mixing a primary color with it's compliment (that's the secondary color directly across the wheel from it) should make black because a the secondary color has the other two primary colors. In practice, though, the color will be some form of gray. Yellow and Indigo results in a blue/gray. Magenta and green creates dark brown. Cyan and Red makes a purple/gray and so on.

These funny grays are actually quite useful and can add greater depth to your work. Lets say you have a red ball that has a shadow cast across half of it. The shadow could be made by adding black to the red to get a deeper red but it might come out looking a little flat. Try adding some of its compliment (in this case, cyan) to the mix. The shadows will take on greater depth and the highlight will seem brighter.

 

Click on the image
to see a larger version
Red, black and white only (monochromatic scheme) Red, cyan, black and white (complimentary scheme)