Adobe Wide Gamut RGB color space
Encyclopedia
RGB color space
An RGB color space is any additive color space based on the RGB color model. A particular RGB color space is defined by the three chromaticities of the red, green, and blue additive primaries, and can produce any chromaticity that is the triangle defined by those primary colors...
developed by Adobe Systems
Adobe Systems
Adobe Systems Incorporated is an American computer software company founded in 1982 and headquartered in San Jose, California, United States...
, that offers a large gamut
Gamut
In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
by using pure spectral primary color
Primary color
Primary colors are sets of colors that can be combined to make a useful range of colors. For human applications, three primary colors are usually used, since human color vision is trichromatic....
s.
It is able to store a wider range of color values than sRGB or Adobe RGB
Adobe RGB color space
The Adobe RGB color space is an RGB color space developed by Adobe Systems in 1998. It was designed to encompass most of the colors achievable on CMYK color printers, but by using RGB primary colors on a device such as the computer display...
color spaces. As a comparison, the wide-gamut RGB color space encompasses 77.6% of the visible colors specified by the Lab color space
Lab color space
A Lab color space is a color-opponent space with dimension L for lightness and a and b for the color-opponent dimensions, based on nonlinearly compressed CIE XYZ color space coordinates....
, whilst the standard Adobe RGB color space covers just 50.6% and sRGB covers only 35.0%.
When working in color spaces with such a large gamut
Gamut
In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain complete subset of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circumstance, such as within a given color space or by a...
, it is recommended to work in 16-bit per channel color depth to avoid posterization
Posterization
Posterization of an image entails conversion of a continuous gradation of tone to several regions of fewer tones, with abrupt changes from one tone to another. This was originally done with photographic processes to create posters...
effects. This will occur more frequently in 8-bit per channel modes as the gradient steps are much larger.
As with sRGB, the color component values in wide-gamut RGB are not proportional to the luminances. Similar to Adobe RGB, a gamma
Gamma correction
Gamma correction, gamma nonlinearity, gamma encoding, or often simply gamma, is the name of a nonlinear operation used to code and decode luminance or tristimulus values in video or still image systems...
of 2.2 is assumed, without the linear segment near zero that is present in sRGB. The precise gamma value is
, or 2.19921875.The white point
White point
A white point is a set of tristimulus values or chromaticity coordinates that serve to define the color "white" in image capture, encoding, or reproduction. Depending on the application, different definitions of white are needed to give acceptable results...
corresponds to D50.
The chromaticities of the primary colors and the white point are as follows:
| Color | CIE x | CIE y | Wavelength |
|---|---|---|---|
| Red | 0.7347 | 0.2653 | 700 nm |
| Green | 0.1152 | 0.8264 | 525 nm |
| Blue | 0.1566 | 0.0177 | 450 nm |
| White point | 0.3457 | 0.3585 |