クロマ（彩度）

Chroma is distinct from saturation, though the two are often confused. Chroma measures colorfulness in absolute terms relative to a reference white, while saturation measures it relative to the color's own brightness. A color with high chroma is vivid and intense, while a color with zero chroma is a pure gray. The Munsell color system was among the first to separate chroma as an independent dimension. In modern color science, CIELAB and OKLCH both use chroma as a key axis, making it essential for perceptually uniform color manipulation.