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Wide-gamut RGB color space

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CIE 1931 xy chromaticity diagram showing the gamut of the wide-gamut RGB color space and location of the primaries. The D50 white point is shown in the center.

The wide-gamut RGB color space (or Adobe Wide Gamut RGB) is a color space developed by Adobe Systems, that offers a large gamut by using pure spectral primary colors.[1] It is able to store a wider range of color values than sRGB or Adobe RGB color spaces. As a comparison, the wide-gamut RGB color space encompasses 77.6% of the visible colors specified by the CIELAB color space, while the standard Adobe RGB color space covers just 52.1%[2] and sRGB covers only 35.9%.[3]

When working in color spaces with such a large gamut, it is recommended to work in 16-bit per channel color depth to avoid posterization effects. This will occur more frequently in 8-bit per channel modes as the gradient steps are much larger.[4]

As with sRGB, the color component values in wide-gamut RGB are not proportional to the luminances. Similar to Adobe RGB, a gamma of 2.2 is assumed, without the linear segment near zero that is present in sRGB. The precise gamma value is 563/256, or 2.19921875.

The white point 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

References

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  1. ^ Pascale, Danny. "A Review of RGB Color Spaces ...from xyY to R'G'B'" (PDF). Retrieved February 12, 2010.
  2. ^ Adobe RGB color space
  3. ^ Rec. 709
  4. ^ Rodney, Andrew. "The role of working spaces in Adobe applications" (PDF). Retrieved February 12, 2010.