CMYK color model

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CMYK Color Swatches.svg
Ink used in four-color printing: cyan, magenta, yellow, and black.
CMYK color model.svg
Pairwise combinations of cyan, magenta, and yellow inks produce red, green, and blue. All three combined produce an imperfect black.
CMYK closeup.jpg
CMYK under a microscope.jpg
A color perceived as cerulean ( ) is a blend of cyan, magenta, yellow, and black inks, as observed under magnification.

The CMYK color model is a subtractive color model used in color printing as well as describing the printing process. The abbreviation CMYK refers to the four color components used in printing: cyan, magenta, yellow, and black (the key plate). [1]

Contents

In subtractive models, inks reduce the amount of light reflected from a white or light background. White is the color of the substrate, and black results from the combination of inks. This contrasts with additive color models (e.g., RGB color model), where colors are produced by emitting light, white results from combining all primary colors, and black represents the absence of light. The addition of black ink reduces ink consumption and produces more consistent dark tones compared to using cyan, magenta, and yellow alone.

The CMYK printing process was first implemented in the 1890s for color newspaper illustrations and comic strips.

Halftoning

Diagram showing color halftoning with CMYK separations. The combined halftone pattern appears as a uniform color to the human eye at sufficient viewing distance. Halftoningcolor.svg
Diagram showing color halftoning with CMYK separations. The combined halftone pattern appears as a uniform color to the human eye at sufficient viewing distance.

Halftoning (or screening) allows a printer to produce continuous tones by varying the size and spacing of small ink dots. This creates the perception of intermediate colors between the primary inks. For example, 20% coverage of magenta ink produces a pink tone rather than full magenta. [2] [3]

Without halftoning, CMYK inks would only produce eight colors: the three primaries (cyan, magenta, yellow), the three secondaries (red, green, blue), white, and black.

Comparison to CMY

Barns grand tetons.jpg
CMY separation - no black.jpg
CMYK separation - maximum black.jpg
Comparison of printing separations: CMY (left) vs CMYK (right).
CMYK ink on offset-printed paper CMYK offset on paper2.jpg
CMYK ink on offset-printed paper

CMYK is an extension of the CMY model, which omits black ink. Black ink is added in four-color printing for several practical reasons: [4]

A dark area printed with CMY and then overlaid with black is referred to as rich black. [6]

Techniques such as under color removal, under color addition, and gray component replacement determine the amount of black ink relative to other inks. [7]

Other printer color models

CMYK contrasts with spot color printing, where specific inks produce fixed colors. Some presses can combine process and spot colors. High-quality printed materials often require full-color process printing, sometimes augmented with spot colors or metallic inks. [8] [9]

Extended gamut systems (e.g., CMYKOG Hexachrome) increase the range of reproducible colors beyond standard CMYK. [10]

Comparison with RGB displays

Comparison of RGB and CMYK gamuts on the CIE 1931 xy chromaticity diagram CIE1931xy gamut comparison.svg
Comparison of RGB and CMYK gamuts on the CIE 1931 xy chromaticity diagram

RGB displays emit light and produce additive colors, while CMYK inks absorb light and produce subtractive colors. [11] Each model has a distinct color gamut; colors visible on one may not be reproducible on the other. [12]

Spectrum of printed paper

The CMYK model codes for absorption of light. Cyan absorbs red, magenta absorbs green, and yellow absorbs blue. Black ideally absorbs all wavelengths. [13]

Spectrum of printed wavelengths on paper. Readings from several flower petals are shown for comparison. CMYK Spectrum printed paper.pdf
Spectrum of printed wavelengths on paper. Readings from several flower petals are shown for comparison.

Conversion

RGB and CMYK are device-dependent; no universal formula converts between them. Color management systems using ICC profiles are required to map between devices accurately. Conversion depends on device gamuts, rendering intents, and factors such as dot gain and Neugebauer primaries. [14]

Predefined printing standards, such as Specifications for Web Offset Publications, include ICC profiles for software and operating systems. [15]

See also

References

  1. ↑ Mixam Print Support: CMYK colour charts and values.
  2. ↑ Kang, Henry R. (1999). Digital Color Halftoning. SPIE Press. p. 1. ISBN   0-8194-3318-7.
  3. ↑ Hibit, Eric (2022-07-29). Color Theory For Dummies. John Wiley & Sons. p. 192. ISBN   978-1-119-89228-1.
  4. ↑ Roger Pring (2000). WWW.Color. Watson–Guptill. p. 178. ISBN   0-8230-5857-3.
  5. ↑ Menegus, Bryan (May 20, 2016). "The Difference Between RGB and CMYK, Explained". Gizmodo. Retrieved October 4, 2020.
  6. ↑ R. S. Hodges (2003). The Guild Handbook of Scientific Illustration. John Wiley and Sons. p. 242. ISBN   0-471-36011-2.
  7. ↑ Kipphan, Helmut, ed. (2001). Handbook of Print Media: Technologies and Production Methods. Springer. p. 87. ISBN   3-540-67326-1.
  8. ↑ Collins, Wayne; Bahr, Alex; Kuo, Gwen (2020). Graphic Design and Print Production Fundamentals. Graphic Communications Open Press. Archived from the original on November 3, 2025. Retrieved December 23, 2025. Process colors are typically used when a design requires full-color printing or when it includes complex images like photographs.
  9. ↑ Davies, Helen (August 3, 2020). "Top 8 Large Format Printing Tips To Achieve High-End Projects". Front Signs. Archived from the original on September 29, 2020. Retrieved October 4, 2020.
  10. ↑ Zeng, Huanzhao (2003). "3-D Color Separation Maximizing the Printer Gamut". Proceedings of SPIE. 5008: 260. doi:10.1117/12.472012.
  11. ↑ Stone, Maureen C. (2003). A Field Guide to Digital Color. A K Peters/CRC Press. p. 11. ISBN   978-1568811611.
  12. ↑ Wyszecki, Günther; Stiles, W. S. (2000). Color Science: Concepts and Methods, Quantitative Data and Formulae (2nd ed.). Wiley-Interscience. p. 174. ISBN   978-0471399186.
  13. ↑ "Subtractive Color Mixing". L. R. Ingersoll Physics Museum. Retrieved October 4, 2020.
  14. ↑ Gaurav Sharma (2003). Digital Color Imaging Handbook. CRC Press. p. 68. ISBN   0-8493-0900-X.
  15. ↑ "KB933845 How to obtain and install the Microsoft Standard CMYK Profile (RSWOP.icm) in Windows Vista". Beta Archive. March 15, 2007. Retrieved 1 September 2023.
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