CMYK is made of four letters: Cyan, Magenta, Yellow and Key (or Black). By combining these four inks, print shops produce almost all the colors needed on paper.
Why a separate black?#
Mixing the other three colors does not make a pure black; it usually turns out a dark brown. Adding black ink also makes text sharper and reduces the cost of ink.
A subtractive model#
Unlike RGB, which works with light, CMYK is a "subtractive" model: ink absorbs light. The more ink, the darker the color, and white paper is the base of the light.
An example#
You want to print business cards. Your logo is a bright, glowing blue in the design. Because that blue is defined in RGB, it may print duller. If you build the file in CMYK from the start, you see on screen the same color that print can actually produce, and you are not surprised.
Where it is used#
- Brochures, books, posters and banners
- Packaging
- Business cards and letterheads
- Printing on fabric with common methods
Practical tips#
- Create print files in CMYK mode from the start
- Get a printed proof before a large print run
- Neon and very bright colors cannot be reproduced exactly with ordinary printing
- Consult the print shop about file specifications