CMYK (Cyan, Magenta, Yellow, Key/Black) is a subtractive color model used primarily in color printing. Unlike the additive RGB model used for digital displays, CMYK works by partially or entirely masking colors on a lighter background.
Understanding CMYK Components
The CMYK color model consists of four components:
- Cyan (C): A blue-green color that absorbs red light
- Magenta (M): A purplish-red color that absorbs green light
- Yellow (Y): A color that absorbs blue light
- Key/Black (K): Used to improve shadow detail and overall color depth
The "K" in CMYK stands for "Key" rather than "Black" because in four-color printing, cyan, magenta, and yellow printing plates are carefully keyed or aligned with the key plate, which is usually black.
How CMYK Works
CMYK is a subtractive color model, which means:
- It starts with a white surface (like paper) that reflects all light
- Inks applied to the surface subtract portions of the color spectrum
- The more ink applied, the more light is absorbed, resulting in darker colors
- When all inks are applied at 100%, the result should theoretically be black, though in practice it's often a muddy brown
This is why a separate black (K) component is used - it provides true black and better shadow detail than mixing the other three colors.
CMYK Color Values
CMYK colors are specified as percentages of each ink component:
/* CMYK notation examples */
cmyk(0%, 100%, 100%, 0%) /* Pure red */
cmyk(100%, 0%, 100%, 0%) /* Pure green */
cmyk(100%, 100%, 0%, 0%) /* Pure blue */
cmyk(0%, 0%, 0%, 100%) /* Pure black */
cmyk(0%, 0%, 0%, 0%) /* No ink (white) */CMYK vs. RGB
The fundamental difference between CMYK and RGB is how they create colors:
| CMYK (Subtractive) | RGB (Additive) |
|---|---|
| Used for print media | Used for digital displays |
| Starts with white (all light reflected) | Starts with black (no light) |
| Adds inks to absorb light | Adds light to create colors |
| More ink = darker colors | More light = brighter colors |
| Primary colors: Cyan, Magenta, Yellow | Primary colors: Red, Green, Blue |
| Limited color gamut compared to RGB | Wider color gamut than CMYK |
Color Gamut Limitations
CMYK has a smaller color gamut (range of reproducible colors) than RGB. This means:
- Some vibrant colors visible on screen cannot be reproduced in print
- When converting from RGB to CMYK, colors often appear duller or less saturated
- Professional designers must account for these differences when creating work for both digital and print media
CMYK in Professional Printing
In professional printing, CMYK is the standard color model, but it's often extended with:
- Spot colors: Pre-mixed inks (like Pantone colors) for consistent color reproduction
- Extended color gamuts: Systems that add orange, green, violet, or other inks to expand the reproducible color range
- Special inks: Metallic, fluorescent, or other specialty inks for effects that cannot be achieved with standard CMYK
Converting Between CMYK and RGB
Converting between CMYK and RGB is not a straightforward process due to their different color gamuts:
- The conversion is not perfectly reversible and can result in color shifts
- Professional color management systems use color profiles to achieve the best possible conversion
- For web developers, it's generally best to work in RGB and let professional print services handle conversion to CMYK
For web applications, you can use our color conversion tools to work with different color formats: