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Subtractive colors

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Subtractive color mixing




Conversely, additive color systems start without light (black). Light sources of various wavelengths combine to make a color. In either type of system, three primary colors are combined to stimulate humans’ trichromatic color vision, sensed by the three types of cone cells in the eye, giving an apparently full range.

Wavelength absorbsion

The following flowchart illustrates an example of the process, step by step.

Light source S M L White light radiates from the light source.
Cyan ink S M Cyan ink absorbs long wavelengths, allowing the rest to pass through.
Yellow ink M L Yellow ink absorbs short wavelengths, allowing the rest to pass through. The only wavelengths remaining are medium, which are green.
Paper S M L The medium wavelengths reflect off of the paper.
Yellow ink M L The medium wavelengths pass back through the yellow ink.
Cyan ink S M The medium wavelengths pass back through the cyan ink.
Retina S M L The medium wavelengths activate the M cones in the retina.
Brain S M L The brain interprets the signal from the M cones as green.

In order to fully understand the process, it should be demonstrated how black is obtained using red, green, and blue.

Green ink M Green ink absorbs short and long wavelengths, allowing medium wavelengths to pass through.
Red ink L Red ink absorbs short and medium wavelengths, allowing long wavelengths to pass through. However, there are no long wavelengths remaining to pass through, and all of the light has been absorbed.


File:BYR color wheel.svg
Main article: RYB color model

RYB (Red, Yellow, Blue) is the formerly standard set of subtractive primary colors used for mixing pigments. It is used in art and art education, particularly in painting. It predated modern scientific color theory.

Red, yellow, and blue are the primary colors of the standard color "wheel". The secondary colors, violet (or purple), orange, and green (VOG) make up another triad, formed by mixing equal amounts of red and blue, red and yellow, and blue and yellow, respectively.

The RYB primary colors became the foundation of 18th century theories of color vision as the fundamental sensory qualities blended in the perception of all physical colors and equally in the physical mixture of pigments or dyes. These theories were enhanced by 18th-century investigations of a variety of purely psychological color effects, in particular the contrast between "complementary" or opposing hues produced by color afterimages and in the contrasting shadows in colored light. These ideas and many personal color observations were summarized in two founding documents in color theory: the Theory of Colors (1810) by the German poet and government minister Johann Wolfgang von Goethe, and The Law of Simultaneous Color Contrast (1839) by the French industrial chemist Michel-Eugène Chevreul.

CMYK printing process

Main article: CMYK color model

In most color printing, the primary ink colors used are cyan, magenta, and yellow. Cyan is the complement of red, meaning that cyan acts like a filter that absorbs red. The amount of cyan applied to a paper will control how much red will show. Magenta is the complement of green, and yellow the complement of blue. Combinations of different amounts of the three inks can produce a wide range of colors; this is how artwork reproductions are mass-produced, although an under-toning of black ink is usually used as well. This mixture is called CMYK.

See also


Wikimedia Commons has media related to:
  • Berns, Roy S. (2000). Billmeyer and Saltzman's Principles of Color Technology, 3rd edition, Wiley, New York.
  • Stroebel, Leslie, John Compton, Ira Current, and Richard Zakia (2000). Basic Photographic Materials and Processes, 2nd edition, Focal Press, Boston.
  • Wyszecki, Günther and W. S. Stiles (1982). Colour Science: Concept and Methods, Quantitative Data and Formulae, Wiley, New York.

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