CMYK
A subtractive color model using cyan, magenta, yellow, and black inks to reproduce colors on paper. It is the standard for commercial printing.
CMYK is a subtractive color model that reproduces colors by layering inks on paper. White light strikes the surface, and each ink layer absorbs specific wavelengths, leaving the remaining light to reach the viewer. While CMY alone can theoretically produce all colors, real-world inks cannot create a deep neutral black, so a dedicated black (Key) plate is added.
Each channel is expressed as ink coverage from 0% to 100%. Pure red is C:0% M:100% Y:100% K:0%. The Total Area Coverage (TAC) is generally kept to roughly 300-350% for standard offset printing to prevent drying problems and ink smearing, though the actual limit depends on the press, paper and inks, so follow the printer specification.
- Process color: The standard four-color printing method using halftone dots of varying size and angle to simulate continuous tones. Screen ruling is chosen to suit the paper and press; around 175 lpi is one representative setting for commercial offset printing
- Gamut limitations: The CMYK gamut is narrower than sRGB, particularly in vivid blues and greens. RGB-to-CMYK conversion requires gamut mapping to substitute out-of-gamut colors
- Black generation: GCR (Gray Component Replacement) and UCR (Under Color Removal) replace overlapping CMY with black ink, reducing consumption and improving shadow density
In desktop publishing, files are converted from RGB to CMYK before submission. ICC profile-based conversions with soft-proofing allow designers to simulate printed output on screen, catching gamut issues before committing to print runs.