Gamut mapping / compression

Gamut mapping is the color half of rendering an image to a display: a saturated color that falls outside the delivery gamut triangle (from the CIE diagram) has to be brought inside it. There are two ways. Clipping slams it flat onto the boundary — fast, but it flattens detail in saturated areas and often shifts hue (a clipped bright red drifts orange). Compression eases the outer colors smoothly inward, keeping their relative shape and hue at the cost of a little saturation. Compression is almost always the right answer — it’s why “gamut compression” is a checkbox worth enabling in a CST, and why ACES added a dedicated gamut-compress step. When reds “block up” or a neon sign “loses its shape,” that’s a gamut problem, not a tone-mapping one.

First used in: 3.2 · Tone & gamut mapping, DRTs