sRGB

sRGB is a standard RGB color space designed to match typical consumer display devices and the conditions of viewing images on the web. It was developed jointly by Hewlett-Packard and Microsoft in 1996 to provide a single, interoperable color space for digital images, graphics, and user interfaces. The color space is formally defined in IEC 61966-2-1 and is widely adopted as the default color space for photographs, videos, and many software applications.

The sRGB color space uses specific primary colors and a defined white point. The primaries are red (x=0.640, y=0.330), green (x=0.300, y=0.600), and blue (x=0.150, y=0.060) in the CIE 1931 chromaticity diagram, and the white point is D65, corresponding to a correlated color temperature of about 6500 K. The standard specifies a nonlinear transfer function that maps linear light values to encoded sRGB values and back, enabling efficient storage and display across devices.

The encoding and decoding functions are piecewise. For an encoded sRGB value in the range 0 to 1, the linear light value is calculated as linear = srgb/12.92 if srgb ≤ 0.04045; otherwise linear = ((srgb + 0.055)/1.055)²·⁴. The inverse is srgb = 12.92·linear if linear ≤ 0.0031308; otherwise srgb = 1.055·(linear)^(1/2.4) − 0.055. This gamma-like curve preserves perceptual uniformity for typical displays and content.

Usage and scope: sRGB is the de facto standard for web images and many operating systems, viewers, and image editors. Its main limitation is a relatively small gamut compared to wide-gamut spaces like Adobe RGB, making it less suitable for certain professional print workflows without color management.