SUBTRACTIVE COLOR

A 'subtractive color' model explains the mixing of paints, dyes, inks, and natural colorants to create a range of colors, where each such color is caused by the mixture absorbing some wavelengths of light and reflecting others. The color that an opaque object appears to have is based on what parts of the electromagnetic spectrum are reflected by it, or conversely by what parts of the spectrum are not absorbed.
Subtractive color systems start with white light. Certain wavelengths are subtracted from this white light by means of colored inks, paints or films placed between the viewer and the light source or reflective surface (such as white paper), creating the resultant color.
Conversely, an additive color system is a system that starts with no light (black) and wavelengths are added to produce different colors by means of adding light sources. In either an additive or a subtractive system, three primary colors are needed to match the trichromatic color vision of humans, since humans normally have three different types of cone cells in the eye.

Contents

CMYK printing process

RYB

See also

References

CMYK printing process

Main articles: 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, though for various reasons a black ink is usually used as well. This mixture of cyan, magenta, yellow and black is commonly called CMYK. CMYK is therefore an example of a subtractive color model.

RYB

Main articles: RYB color model

RYB is a historical set of subtractive primary colors. It is primarily used in art and art education, particularly painting. It predates modern scientific color theory.
RYB make up the primary color triad in a standard color wheel. The secondary colors VOG also make up another triad. Triads are formed by 3 equidistant colors on a particular color wheel.
The RYB primary colors became the foundation of 18th century theories of color vision, as the fundamental sensory qualities that are 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 that are 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.

See also

★ CMYK color model

★ Additive color

★ Color film (motion picture)

★ Primary color

References

★ Billmeyer and Saltzman's Principles of Color Technology, 3rd edition, Berns, Roy S., , , Wiley, New York, 2000, ISBN 0-471-19459-X

★ Basic Photographic Materials and Processes, 2nd edition, Stroebel, Leslie, John Compton, Ira Current, and Richard Zakia, , , Focal Press, Boston, 2000, ISBN 0-240-80405-8

★ Colour Science Concept and Methods, Quantitative Data and Formulae, Wyszecki, Günther and W. S. Stiles, , , Wiley, New York, 1982, ISBN 0-471-02106-7