sRGB is the default internet color space, matching Rec. 709 primaries with D65 white point

sRGB (Standard RGB) is the de facto default for web images, CSS colors, and most display content. Defined by HP and Microsoft in 1996, its primaries match Rec. 709 (HDTV) and its white point is D65. Any untagged RGB image on the web is assumed sRGB. When a shader works with vec3 colors loaded from a plain PNG, those values are sRGB-encoded and must be linearized before physically-based math. sRGB covers roughly 35% of human-visible colors and is the baseline all other consumer spaces are compared against.

Examples

CSS color #3498db is sRGB. Browsers render it assuming sRGB. Most PNG/JPEG files are sRGB unless otherwise tagged. sRGB primaries share coordinates with Rec. 709 (HDTV).

Assessment

You load a PNG texture into a WebGL shader. The sampled values go directly into a physically-based lighting calculation. What must you do to the values first, and why?