CMYK color model - wikipedia CMYK color model `` CMYK '' redirects here. For the extended play by James Blake, see CMYK ( EP ). `` CMYB '' redirects here. For the cMyb gene, see MYB ( gene ). This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. ( May 2017 ) Color printing typically uses ink of four colors : cyan, magenta, yellow, and black. When CMY `` primaries '' are combined at full strength, the resulting `` secondary '' mixtures are red, green, and blue. Mixing all three gives an imperfect black or a perfect grey. What appears as cerulean ( ) in the top image is actually a blend of cyan, magenta, yellow and black, as magnification under a microscope demonstrates. The CMYK color model ( process color, four color ) is a subtractive color model, used in color printing, and is also used to describe the printing process itself. CMYK refers to the four inks used in some color printing : cyan, magenta, yellow, and key ( black ). The reason for black ink being referred to as key is because in four - color printing, cyan, magenta, and yellow printing plates are carefully keyed, or aligned, with the key of the black key plate. Some sources suggest that the `` K '' in CMYK comes from the last letter in `` black '' and was chosen because B already means blue. However, some people disagree with this because there is no blue in the primary CMYK colors ; it is made with cyan and magenta. Some sources claim this explanation, although useful as a mnemonic, is incorrect, that K comes only from `` Key '' because black is often used as outline and printed first. It is more common in modern printing for the black to be printed last in order to yield deeper, cleaner shadows and crisper blacks than the imperfect black created by the CMY combination when those colors are printed over the black. 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. Contents 1 Halftoning 1.1 Screen angle 2 Benefits of using black ink 3 Other printer color models 4 Comparison with RGB displays 4.1 Spectrum of printed paper 5 Conversion 6 See also 7 References 8 External links Halftoning This diagram shows three examples of color halftoning with CMYK separations, as well as the combined halftone pattern and how the human eye would observe the combined halftone pattern from a sufficient distance. Main article : Halftone With CMYK printing, halftoning ( also called screening ) allows for less than full saturation of the primary colors ; tiny dots of each primary color are printed in a pattern small enough that humans perceive a solid color. Magenta printed with a 20 % halftone, for example, produces a pink color, because the eye perceives the tiny magenta dots on the large white paper as lighter and less saturated than the color of pure magenta ink. Without halftoning, the three primary process colors could be printed only as solid blocks of color, and therefore could produce only seven colors : the three primaries themselves, plus three secondary colors produced by layering two of the primaries : cyan and yellow produce green, cyan and magenta produce blue, yellow and magenta produce red ( these subtractive secondary colors correspond roughly to the additive primary colors ), plus layering all three of them resulting in black. With halftoning, a full continuous range of colors can be produced. Screen angle Typical halftone screen angles. Main article : Screen angle To improve print quality and reduce moiré patterns, the screen for each color is set at a different angle. While the angles depend on how many colors are used and the preference of the press operator, typical CMYK process printing uses any of the following screen angles : C 15 ° 15 ° 105 ° 165 ° 75 ° 45 ° 75 ° 45 ° Y 0 ° 0 ° 90 ° 90 ° 45 ° 75 ° 15 ° 105 ° Benefits of using black ink A color photograph of the Teton Range. The image above, separated for printing with process cyan, magenta, and yellow inks. The same image, this time separated with maximum black, to minimize colored - inks use. 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 colored 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. Other printer color models CMYK or process color printing is contrasted with spot color printing, in which specific colored inks are used to generate the colors appearing on paper. Some printing presses are capable of printing with both four - color process inks and additional spot color inks at the same time. High - quality printed materials, such as marketing brochures and books, often include photographs requiring process - color printing, other graphic effects requiring spot colors ( such as metallic inks ), and finishes such as varnish, which enhances the glossy appearance of the printed piece. CMYK are the process printers which often have a relatively small color gamut. Processes such as Pantone 's proprietary six - color ( CMYKOG ) Hexachrome considerably expand the gamut. Light, saturated colors often can not be created with CMYK, and light colors in general may make visible the halftone pattern. Using a CcMmYK process, with the addition of light cyan and magenta inks to CMYK, can solve these problems, and such a process is used by many inkjet printers, including desktop models. Comparison with RGB displays Comparison of some RGB and CMYK color gamut on a CIE 1931 xy chromaticity diagram. Comparisons between RGB displays and CMYK prints can be difficult, since the color reproduction technologies and properties are very different. A computer monitor mixes shades of red, green, and blue light to create color pictures. A CMYK printer instead uses light - absorbing cyan, magenta, and yellow inks, whose colors are mixed using dithering, halftoning, or some other optical technique. Similar to monitors, the inks used in printing produce a color gamut that is `` only a subset of the visible spectrum '' although both color modes have their own specific ranges. As a result of this items which are displayed on a computer monitor may not completely match the look of items which are printed if opposite color modes are being combined in both mediums. When designing items to be printed, designers view the colors which they are choosing on an RGB color mode ( their computer screen ), and it is often difficult to visualize the way in which the color will turn out post-printing because of this. Spectrum of printed paper To reproduce color, the CMYK color model codes for absorbing light rather than emitting it ( as is assumed by RGB ). The ' K ' component absorbs all wavelengths and is therefore achromatic. The Cyan, Magenta, and Yellow components are used for color reproduction and they may be viewed as the inverse of RGB. Cyan absorbs Red, Magenta absorbs Green, and Yellow absorbs Blue ( - R, - G, - B ). Spectrum of the visible wavelengths on printed paper ( SCA Graphosilk ). Shown is the transition from Red to Yellow. White, red, blue, and green are shown for reference. Readings from a white orchid flower, a rose ( red and yellow petals ), and a red cyclamen flower are shown for comparison. The units of spectral power are simply raw sensor values ( with a linear response at specific wavelengths ). Conversion Early representation of the three - color process ( 1902 ). Since RGB and CMYK spaces are both device - dependent spaces, there is no simple or general conversion formula that converts between them. Conversions are generally done through color management systems, using color profiles that describe the spaces being converted. Nevertheless, the conversions can not be exact, particularly where these spaces have different gamuts. The problem of computing a colorimetric estimate of the color that results from printing various combinations of ink has been addressed by many scientists. A general method that has emerged for the case of halftone printing is to treat each tiny overlap of color dots as one of 8 ( combinations of CMY ) or of 16 ( combinations of CMYK ) colors, which in this context are known as Neugebauer primaries. The resultant color would be an area - weighted colorimetric combination of these primary colors, except that the Yule -- Nielsen effect ( `` dot gain '' ) of scattered light between and within the areas complicates the physics and the analysis ; empirical formulas for such analysis have been developed, in terms of detailed dye combination absorption spectra and empirical parameters. See also CcMmYK color model Cycolor Grey component replacement Jacob Christoph Le Blon SWOP CMYK standard References Jump up ^ Galer, Mark ; Horvat, Les ( 2003 ). Digital Imaging : Essential Skills. Focal Press. p. 74. ISBN 978 - 0 - 240 - 51913 - 5. Jump up ^ Jennings, Simon ( 2003 ). Artist 's Color Manual : The Complete Guide to Working with Color. Chronicle Books LLC. p. 21. ISBN 978 - 0 - 8118 - 4143 - 6. Jump up ^ Gatter, Mark ( 2004 ). Getting It Right in Print : Digital Pre-press for Graphic Designers. Laurence King Publishing. p. 31. ISBN 978 - 1 - 85669 - 421 - 6. Jump up ^ Campbell, Alastair. The Designer 's Lexicon. 2000 Chronicle, San Francisco. p 192 Jump up ^ McCue, Claudia. Real World Print Production. 2007 Peachpit, Berkeley. p 31. Jump up ^ Roger Pring ( 2000 ). WWW. Color. Watson -- Guptill. ISBN 0 - 8230 - 5857 - 3. Jump up ^ R.S. Hodges ( 2003 ). The Guild Handbook of Scientific Illustration. John Wiley and Sons. ISBN 0 - 471 - 36011 - 2. Jump up ^ Carla Rose ( 2003 ). Sams Teach Yourself Adobe Photoshop Elements 2 in 24 Hours. Sams Publishing. ISBN 0 - 672 - 32430 - X. Jump up ^ Damien van Holten, print international.org, `` RGB Vs CMYK '' http://www.printernational.org/rgb-versus-cmyk.php ^ Jump up to : Gaurav Sharma ( 2003 ). Digital Color Imaging Handbook. CRC Press. ISBN 0 - 8493 - 0900 - X. External links Wikimedia Commons has media related to CMYK. XCmyk -- CMYK to RGB Calculator with source code Color Space Fundamentals -- animated illustration of RGB vs. CMYK Color space List of color spaces Color models CAM CIECAM02 iCAM CIE CIEXYZ CIELAB CIECAM02 CIELUV Yuv CIEUVW CIE RGB RGB RGB color space sRGB rg chromaticity Adobe Wide - gamut ProPhoto scRGB DCI - P3 Rec. 709 Rec. 2020 Rec. 2100 YUV YUV PAL YDbDr SECAM PAL - N YIQ NTSC YCbCr Rec. 601 Rec. 709 Rec. 2020 Rec. 2100 ICtCp YPbPr xvYCC YCoCg Other CcMmYK CMYK Coloroid LMS Hexachrome HSL, HSV HCL Imaginary color OSA - UCS PCCS RG RYB Color systems and standards ACES ANPA Colour Index International CI list of dyes DIC Federal Standard 595 HKS ICC profile ISCC -- NBS Munsell NCS Ostwald Pantone RAL list For the vision capacities of organisms or machines, see Color vision. Photography Outline Terminology 35 mm equivalent focal length Angle of view Aperture Black and white Chromatic aberration Circle of confusion Color balance Color temperature Depth of field Depth of focus Exposure Exposure compensation Exposure value Zebra patterning F - number Film format Large Medium Film speed Focal length Guide number Hyperfocal distance Metering mode Orb ( optics ) Perspective distortion Photograph Photographic printing Photographic processes Reciprocity Red - eye effect Science of photography Shutter speed Sync Zone System Genres Abstract Aerial Architectural Astrophotography Banquet Conceptual Conservation Cloudscape Documentary Ethnographic Erotic Fashion Fine - art Fire Forensic Glamour High - speed Landscape Lomography Nature Neues Sehen Nude Photojournalism Pornography Portrait Post-mortem Selfie Social documentary Sports Still life Stock Street Vernacular Underwater Wedding Wildlife Techniques Afocal Bokeh Brenizer Burst mode Contre - jour Cyanotype ETTR Fill flash Fireworks Harris shutter HDRI High - speed Holography Infrared Intentional camera movement Kirlian Kite aerial Long - exposure Macro Mordançage Multiple exposure Night Panning Panoramic Photogram Print toning Redscale Rephotography Rollout Scanography Schlieren photography Sabatier effect Slow motion Stereoscopy Stopping down Strip Slit - scan Sun printing Tilt -- shift Miniature faking Time - lapse Ultraviolet Vignetting Xerography Composition Diagonal method Framing Headroom Lead room Rule of thirds Simplicity Golden triangle ( composition ) Equipment Camera light - field field instant pinhole press rangefinder SLR still TLR toy view Darkroom enlarger safelight Film base format holder stock Filter Flash beauty dish cucoloris gobo hood hot shoe monolight Reflector snoot Softbox Lens Wide - angle lens Zoom lens Telephoto lens Manufacturers Monopod Movie projector Slide projector Tripod head Zone plate History Timeline of photography technology Analog photography Autochrome Lumière Box camera Calotype Camera obscura Daguerreotype Dufaycolor Heliography Painted photography backdrops Photography and the law Glass plate Visual arts Digital photography Digital camera D - SLR comparison MILC camera back Digiscoping Digital versus film photography Film scanner Image sensor CMOS APS CCD Three - CCD camera Foveon X3 sensor Image sharing Pixel Color photography Color Print film Reversal film Color management color space primary color CMYK color model RGB color model Photographic processing Bleach bypass C - 41 process Cross processing Developer Digital image processing Dye coupler E-6 process Fixer Gelatin silver process Gum printing Instant film K - 14 process Print permanence Push processing Stop bath Lists Most expensive photographs Photographers Norwegian Polish street women Portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=CMYK_color_model&oldid=842745165 '' Categories : Color space Printing Printing terminology Hidden categories : Articles needing additional references from May 2017 All articles needing additional references All articles with unsourced statements Articles with unsourced statements from May 2017 Articles with unsourced statements from October 2011 Talk Contents About Wikipedia Azərbaycanca বাংলা Беларуская Български Brezhoneg Català Čeština Dansk Deutsch Eesti Ελληνικά Español Esperanto Euskara فارسی Français Gaeilge Galego 한국어 Հայերեն हिन्दी Hrvatski Bahasa Indonesia Íslenska Italiano עברית Kurdî Latviešu Lietuvių Livvinkarjala Magyar Македонски മലയാളം Bahasa Melayu Nederlands 日本 語 Norsk Occitan Олык марий Polski Português Română Русский Scots Shqip සිංහල Slovenščina Српски / srpski Suomi Svenska Татарча / tatarça ไทย Türkçe Українська Tiếng Việt 粵語 中文 49 more Edit links This page was last edited on 24 May 2018, at 11 : 45. 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Question: how many colors of ink are used to print
Answer: four