page_title: CMYK color model
section_title: Benefits of using black ink
hierarchical_section_title: CMYK color model / Benefits of using black ink
caption_attribution_description: English: The John Moulton Barn on Mormon Row at the base of the Grand Tetons, Wyoming.
context_page_description: The CMYK color model is a subtractive color model, based on the CMY color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four ink plates used in some color printing: cyan, magenta, yellow, and
  key.
  The CMYK model works by partially or entirely masking colors on a lighter, usually white, background. The ink reduces the light that would otherwise be reflected. Such a model is called subtractive because inks "subtract" the colors red, green and blue from white light. White light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow.
  In additive color models, such as RGB, white is the "additive" combination of all primary colored lights, while black is the absence of light. In the CMYK model, it is the opposite: white is the natural color of the paper or other background, while black results from a full combination of colored inks. To save cost on ink, and to produce deeper black tones, unsaturated and dark colors are produced by using black ink instead of the combination of cyan, magenta, and yellow.
context_section_description: The "black" generated by mixing commercially practical cyan, magenta, and yellow inks is unsatisfactory, so four-color printing uses black ink in addition to the subtractive primaries. Common reasons for using black ink include:
  In traditional preparation of color separations, a red keyline on the black line art marked the outline of solid or tint color areas. In some cases a black keyline was used when it served as both a color indicator and an outline to be printed in black because usually the black plate contained the keyline. The K in CMYK represents the keyline or black plate, also sometimes called the key plate.
  Text is typically printed in black and includes fine detail (such as serifs), so to reproduce text or other finely detailed outlines, without slight blurring, using three inks would require impractically accurate registration.
  A combination of 100% cyan, magenta, and yellow inks soaks the paper with ink, making it slower to dry, causing bleeding, or (especially on cheap paper such as newsprint) weakening the paper so much that it tears.
  Although a combination of 100% cyan, magenta, and yellow inks should, in theory, completely absorb the entire visible spectrum of light and produce a perfect black, practical inks fall short of their ideal characteristics and the result is actually a dark muddy color that does not quite appear black. Adding black ink absorbs more light and yields much better blacks.
  Using black ink is less expensive than using the corresponding amounts of colored inks.
  When a very dark area is desirable, a coloured or gray CMY "bedding" is applied first, then a full black layer is applied on top, making a rich, deep black; this is called rich black. A black made with just CMY inks is sometimes called a composite black.
  The amount of black to use to replace amounts of the other ink is variable, and the choice depends on the technology, paper and ink in use. Processes called under color removal, under color addition, and gray component replacement are used to decide on the final mix; different CMYK recipes will be used depending on the printing task.
caption: A color photograph of the Teton Range.
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