Thursday, October 11, 2007

Colour wheel
In the arts of painting, graphic design, and photography, color theory is a body of practical guidance to color mixing and the visual impact of specific color combinations. Although color theory principles first appear in the writings of Alberti (c.1435) and the notebooks of Leonardo da Vinci (c.1490), a tradition of "colory theory" begins in the 18th century, initially within a partisan controversy around Isaac Newton's theory of color (Opticks, 1704) and the nature of so-called primary colors. From there it developed as an independent artistic tradition with only sporadic or superficial reference to colorimetry and vision science.

Color abstractions
Color theory was originally formulated in terms of three "primary" or "primitive" colors -- red, yellow and blue (RYB) -- because these colors were believed capable of mixing all other colors. This color mixing behavior had long been known to printers, dyers and painters, but these trades preferred pure pigments to primary color mixtures, because the mixtures were too dull (unsaturated).
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.
Subsequently, German and English scientists established in the late 19th century that color perception is best described in terms of a different set of primary colors -- red, green and blue violet (RGB) -- modeled through the additive mixture of three monochromatic lights. Subsequent research anchored these primary colors in the differing responses to light by three types of color receptors or cones in the retina. On this basis the quantitative description of color mixture or colorimetry developed in the early 20th century, along with a series of increasingly sophisticated models of color space and color perception.
Across the same period, industrial chemistry radically expanded the color range of lightfast synthetic pigments, allowing for substantially improved saturation in color mixtures of dyes, paints and inks. It also created the dyes and chemical processes necessary for color photography. As a result three-color printing became aesthetically and economically feasible in mass printed media, and the artists' color theory was adapted to primary colors most effective in inks or photographic dyes: cyan, magenta, and yellow (CMY). (In printing, dark colors are supplemented by a black ink, known as the CMYK system; in both printing and photography, white is provided by the color of the paper.) These CMY primary colors were reconciled with the RGB primaries, and subtractive color mixing with additive color mixing, by defining the CMY primaries as substances that absorbed only one of the retinal primary colors: cyan absorbs only red (-R+G+B), magenta only green (+R-G+B), and yellow only blue violet (+R+G-B).
For much of the 19th century artistic color theory either lagged behind scientific understanding or was augmented by science books written for the lay public, in particular Modern Chromatics (1879) by the American physicist Ogden Rood, and early color atlases developed by Albert Munsell (Munsell Book of Color, 1915, see Munsell color system) and Wilhelm Ostwald (Color Atlas, 1919). Major advances were made in the early 20th century by artists teaching or associated with the German Bauhaus, in particular Wassily Kandinsky, Johannes Itten, Faber Birren and Josef Albers, whose writings mix speculation with an empirical or demonstration-based study of color design principles.
Contemporary color theory must address the expanded range of media created by digital media and print management systems, which substantially expand the range of imaging systems and viewing contexts in which color can be used. These applications are areas of intensive research, much of it proprietary; artistic color theory has little to say about these complex new opportunities.

Historical background

Traditional color theory

Main article: Complementary color Complementary colors

Main article: Color temperature Warm vs. cool colors
Any color that lacks strong chromatic content is said to be unsaturated, achromatic, or near neutral. Pure achromatic colors include black, white and all grays; near neutrals include browns, tans, pastels and darker colors. Near neutrals can be of any hue or lightness.
Neutrals are obtained by mixing pure colors with either white or black, or by mixing two complementary colors. In color theory, neutral colors are colors easily modified by adjacent more saturated colors and they appear to take on the hue complementary to the saturated color. Next to a bright red couch, a gray wall will appear distinctly greenish.
Black and white have long been known to combine well with almost any other colors; black increases the apparent saturation or brightness of colors paired with it, and white shows off all hues to equal effect.

Achromatic colors
Any two colors that have the same saturation and lightness are said to have the same nuance. Colors united by nuance are the easiest to combine in color design, regardless of hue, and for that reason are the origin for many of today's muted, earthy or pastel interior design palettes.


Main article: Tints and shades Tints and shades
In painting and other visual arts, two-dimensional color wheels or three-dimensional color solids are used as tools to teach beginners the essential relationships between colors. The organization of colors in a particular color model depends on the purpose of that model: some models show relationships based on Human color perception, whereas others are based on the color mixing properties of a particular medium such as a computer display or set of paints.
Unfortunately, when used in practice, the CMY primary colors often result in color mixtures that lack vibrancy or are relatively unsaturated, especially in the secondary colors: oranges, greens and purples. Printers commonly augment a CYMK palette with spot (trademark specific) ink colors.

Split primary colors
Color theory has long had the goal of predicting or specifying the color combinations that would work well together or appear harmonious. The color wheel has been adopted as tool for defining these basic relationships. Some theorists and artists believe juxtapositions of complementary colors are said to produce a strong contrast or tension,

Color harmony and color meaning
Color theory has not developed an explicit explanation of how specific media affect color appearance: colors have always been defined in the abstract, and whether the colors were inks or paints, oils or watercolors, transparencies or reflecting prints, computer displays or movie theaters, was not considered especially relevant.

Current status

R.W.G Hunt. The Reproduction of Color (6th edition). Wiley & Sons, 2004. : Color Vision. Retrieved April 22, 2005. See also

Munsell color system among the first quantification efforts of color space, still in use today
CIE 1931 color space also known as the CIE XYZ color space
Natural Color System, the reference space for color designation in Sweden and Norway.
CIE L*a*b* color space widely used in the paint industry
RGB color space commonly used for color monitors (based on the RGB color model), and its derivatives, the HSV (hue, saturation, value) and HLS ((hue, lightness, saturation) color spaces.
CMYK color model for color printing and pigments
RYB color model the traditional color model used by artists.
YUV color space for PAL and NTSC television, and the previously used YIQ space

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