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A color wheel or color circle〔http://www.colormatters.com/color-and-design/basic-color-theory〕 is an abstract illustrative organization of color hues around a circle that shows relationships between primary colors, secondary colors, tertiary colors etc. Some sources use the terms ''color wheel'' and ''color circle'' interchangeably; however, one term or the other may be more prevalent in certain fields or certain versions as mentioned above. For instance, some reserve the term ''color wheel'' for mechanical rotating devices, such as color tops or filter wheels. Others classify various color wheels as ''color disc'', ''color chart'', and ''color scale'' varieties. As an illustrative model, artists typically use red, yellow, and blue primaries (RYB color model) arranged at three equally spaced points around their color wheel. Printers and others who use modern subtractive color methods and terminology use magenta, yellow, and cyan as subtractive primaries. Intermediate and interior points of color wheels and circles represent color mixtures. In a paint or subtractive color wheel, the "center of gravity" is usually (but not always) black, representing all colors of light being absorbed; in a color circle, on the other hand, the center is white or gray, indicating a mixture of different wavelengths of light (all wavelengths, or two complementary colors, for example). The arrangement of colors around the color circle is often considered to be in correspondence with the wavelengths of light, as opposed to hues, in accord with the original color circle of Isaac Newton. Modern color circles include the purples, however, between red and violet. Color scientists and psychologists often use the additive primaries, red, green and blue; and often refer to their arrangement around a circle as a color circle as opposed to a color wheel. == Colors of the color wheel == The typical artists' paint or pigment color wheel includes the blue, red, and yellow primary colors. The corresponding secondary colors are green, orange, and violet or purple. The tertiary colors are red–orange, red–violet, yellow–orange, yellow–green, blue–violet and blue–green. A color wheel based on RGB (red, green, blue) or RGV (red, green, violet) additive primaries has cyan, magenta, and yellow secondaries (cyan was previously known as cyan blue). Alternatively, the same arrangement of colors around a circle can be described as based on cyan, magenta, and yellow subtractive primaries, with red, green, and blue (or violet) being secondaries. Most color wheels are based on three primary colors, three secondary colors, and the six intermediates formed by mixing a primary with a secondary, known as tertiary colors, for a total of 12 main divisions; some add more intermediates, for 24 named colors. Other color wheels, however, are based on the four opponent colors, and may have four or eight main colors. Goethe's Theory of Colours provided the first systematic study of the physiological effects of color (1810). His observations on the effect of opposed colors led him to a symmetric arrangement of his color wheel, "for the colours diametrically opposed to each other… are those that reciprocally evoke each other in the eye." (Goethe, ''Theory of Colours'', 1810 ). In this, he anticipated Ewald Hering's opponent color theory (1872).〔(Goethe's Color Theory )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「color wheel」の詳細全文を読む スポンサード リンク
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