The SRGB Gamut
sRGB defines the chromaticities of the red, green, and blue primaries, the colors where one of the three channels is nonzero and the other two are zero. The gamut of chromaticities that can be represented in sRGB is the color triangle defined by these primaries. As with any RGB color space, for non-negative values of R, G, and B it is not possible to represent colors outside this triangle, which is well inside the range of colors visible to a human.
| Chromaticity | Red | Green | Blue | White point |
|---|---|---|---|---|
| x | 0.6400 | 0.3000 | 0.1500 | 0.3128 |
| y | 0.3300 | 0.6000 | 0.0600 | 0.3292 |
| Y | 0.2126 | 0.7153 | 0.0721 | 1.0000 |
sRGB also defines a nonlinear transformation between the intensity of these primaries and the actual number stored. The curve is similar to the gamma response of a CRT display. It is more important to replicate this curve than the primaries to get correct display of an sRGB image. This nonlinear conversion means that sRGB is a reasonably efficient use of the values in an integer-based image file to display human-discernible light levels.
sRGB is sometimes avoided by high-end print publishing professionals because its color gamut is not big enough, especially in the blue-green colors, to include all the colors that can be reproduced in CMYK printing.
Read more about this topic: SRGB