What Color Is Cyan? Understanding CMYK

Contributed by Mary Carroll

In art class, we all learned about the color wheel and the three primary colors: red, yellow and blue. And that when the primary colors are combined, they’ll produce the secondary colors, green, purple and orange. When mixed together in varying combinations, all the many shades and variations on the primary and secondary colors are created. The color wheel refers to the color of pigments (paints).

Monitors and printers use two other methods to display and print color.

Monitors and printers both use primary colors, however, a monitor uses primary additive colors Red, Green and Blue, while printers use the primary subtractive colors Cyan, Magenta and Yellow.

Monitor Color (RGB)
The pigment (color wheel) system does not apply to computer monitors and other display devices such as digital cameras because they are light sources and colors are created on them by adding light. These devices display color using a color model known as RGB.

RGB is an additive color system, meaning that color is added to a black background.

The primary colors of light are red, green and blue, referred to as RGB. In this color system, secondary colors, such as cyan, magenta and yellow, are created by combining the primary colors. White is obtained by adding equal amounts of the primary colors together.

Printers Color (CMYK)
A third color system, subtractive, is used on light reflecting surfaces such as white paper.

The subtractive color system starts with white and subtracts color. CMYK is used in printing as most print projects begin with white paper that reflects white (RGB) light. To reproduce color on the paper, transparent inks or pigments (cyan, magenta and yellow) are used to filter out the RGB wavelengths in various combinations.

The primary colors of the subtractive system are cyan (C), magenta (M) and yellow (Y). The letter "K" in CMYK stands for black. In theory, the combination of cyan, magenta and yellow should produce black, but the fourth color, black, in CMYK is needed to produce a true black. The secondary colors of the subtractive system are red, green and blue.

With CMYK printing, cyan, magenta, yellow, and black (K) inks are printed as tiny dots (screen or line screen). The dots are so small that when they combine visually, your eye sees the full spectrum of color. The mixture of these four colors and is also known as four-color printing, process color, full color and 4C.

One of the challenges of desktop publishing is color matching, or accurately converting RGB colors into CMYK colors, so that the printed piece will appear the same as what appears on the monitor screen. This is done by a process known as dithering.

Dithering
In terms of color, the only thing monitors and printers have in common is dithering.

Dithering is a process that simulates shades of color or gray by creating dots of different patterns and sizes, which overlap and trick the eye into seeing millions of different color shades and hues. Dithering relies on the eye's predisposition to blur dots of different colors by averaging their effects and blending them into a perceived shade or color.

Dithering divides a single pixel into an array of dots so that each dot consists of a primary color or is left vacant to make white.

About the Author:
Mary Carroll is a customer advocate for Video Professor the leader in self-paced software training courses.

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