RYB color model
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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 and does not correspond to the peak responsivities of the trichromat cone cells.
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[edit] Color Wheel
RYB also makes 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. Other common color wheels include the light model and the print model.
[edit] Problems
The RYB space receives criticism for not being able to produce all perceivable colors. In particular, several bright shades of Green, Cyan, and Magenta are not producible from any combination of Red, Yellow, and Blue (and are conspicuously absent from the RYB color wheel).
The reason for this is due to the darkness of Red and Blue. In the RGB color space the colors are added, thus you start with levels of dark colors which are added to produce lighter colors. RYB uses pigments, which are not added, and thus combining colors using the RYB color system will result in a darker color. Because of this it is impossible to create magenta, because its value would normally be the combined value of Red and Blue, but combining them using pigments creates a darker color (namely purple or violet). Because of this any color in between red and blue must be darker than red and blue, and any color between yellow and red or yellow and blue must be darker than yellow.
This incomplete coverage furthermore produces an overall bias to the color space. On the color wheel one can see that the RYB primary colors Red, Yellow, and Blue, are complemented by the secondary colors Green, Purple, and Orange respectively. In an accurate color space mixing a color with its complement would produce a neutral shade of gray. However mixing any primary color with its complement (such as Red and Green) in RYB produces a shade of brown, demonstrating the brown bias of the RYB space.
[edit] Artistic usage
The RYB color theory is favored by many kinds of artists, because impurities in pigments make use of the RGB color model less practical.[citation needed] It is thus well-established as the norm in art, despite its inaccuracies, which are generally either overlooked because of its popularity or simply unnoticed. The reason that the problems with this model are commonly unnoticed is because modern artists combine hundreds of colors and shades in order to produce their desired pigment, not just red, yellow and blue. Combining those three colors in order to produce a specific pigment is so rarely used that, despite the fact that it is still taught, it makes almost no difference whether or not it can actually be done.
[edit] See also
| Color space ■ Color models |
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| RGB color spaces ■ RGB color model ■ CMYK color model ■ HSV color space ■ HSL color space ■ RYB color model ■ CIELAB (L*a*b*) ■ YUV for PAL television ■ YDbDr for SECAM television ■ YIQ for NTSC television |
