RYB color model

RYB (an abbreviation of red-yellow-blue) is a historical set of subtractive primary colors. It is primarily used in art and design education, particularly painting. It predates modern scientific color theory.

Color Wheel

RYB make up the primary color triad in a standard color wheel. The secondary colors VOG (violet-orange-green) also make up another triad. Triads are formed by 3 equidistant colors on a particular color wheel. Other common color wheelsFact|date=August 2007 include the light model and the print model.

History

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 (RGB) -- modeled through the additive, rather than subtractive, mixture of three monochromatic lights.

Painters have long used more than three RYB primary colors in their palettes—and at one point considered red, yellow, blue, and green to be the "four" primaries [For instance Leonardo da Vinci wrote of these four simple colors in his notebook circa 1500. See Rolf Kuenhi. “Development of the Idea of Simple Colors in the 16th and Early 17th Centuries”. "Color Research and Application". Volume 32, Number 2, April 2007.] . Red, yellow, blue, and green are still widely considered the four psychological primary colors [cite book | title = Basic Photographic Materials and Processes | author = Resultby Leslie D. Stroebel, Ira B. Current| publisher = Focal Press| year = 2000 | isbn = 0240803450 | url = http://books.google.com/books?id=BRYa6Qpsw48C&pg=PP1&dq=Basic+Photographic+Materials+and+Processes&sig=3FfkDIRvz8MSinhegznHIKn4AvM] , though red, yellow, and blue are sometimes listed as the "three" psychological primaries [cite book | title = Decorative Painting & Faux Finishes | author = MS Sharon Ross, Elise Kinkead| publisher = Creative Homeowner| year = 2004 | isbn = 1580111793 | url = http://books.google.com/books?id=DPJUWRydR9kC&dq=red+yellow+blue+paint-mixing++subtractive&as_brr=3] , with black and white occasionally added as a fourth and fifth [cite book | title = Dimensional Color | author = Swirnoff, Lois| publisher = W. W. Norton & Company| year = 2003 | isbn = 0393731022 | url = http://books.google.com/books?id=sG5MqtZuFF0C&dq=%22psychological+primaries%22+blue+-green] .

The cyan, magenta, and yellow primary colors associated with CMYK printing are sometimes known as "process blue", "process red", and "process yellow".

Limitations and eccentricities

In the RGB color model the colors are added, so that one starts with levels of dark colors, which are added together to produce lighter colors. RYB uses pigments which are not added, so that combining colors using the RYB color system will result in a darker color. Because of this, it is impossible to create magenta, since 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). Similarly, it is impossible to create a true cyan. Therefore, any color 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.

RYB primary and secondary color hex codes

The hex codes of the primary and secondary colors in the "RYB Color Wheel" shown above are displayed in the color swatches below.

ee also

*Additive color
*Color
*Color solid
*Color theory
*List of colors
*Primary colors
*Subtractive color

References

External links

* [http://delphi4u.awardspace.com/projects.html Delphi4U] - contains project with RYB color space