Wide-gamut RGB color space

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]

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.

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

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.