A color gamut is a subset of colors, usually representing the colors that a display or a printing device can represent.
No display or printer can represent the whole range of colors that a human eye can perceive. The device gamut represents the set that it supports.
Traditionally, in web development, the only gamut used was sRGB (Standard Red-Green-Blue), where each color is described using three bytes, one for each primary color. However, "wide-color" monitors and professional printers support a wider range of colors, that can't be represented using this gamut.
Since 2021, browsers have started to provide functionality for other gamuts, like P3, widely used in the movie industry, and rec2020.
Developers can define different sets of colors for devices supporting larger gamuts using the
color-gamut media feature. They can describe colors outside the RGB gamut using specific CSS functions like
lch() for the LCH cylindrical coordinate system, or
lab() for the Lab coordinate system.
- Gamut on Wikipedia.