Chromaticity is an objective specification of the quality of a color regardless of its luminance. Chromaticity consists of two independent parameters, often specified as hue (h) and colorfulness (s), where the latter is alternatively called saturation, chroma, intensity,[1] or excitation purity.[2][3] This number of parameters follows from trichromacy of vision of most humans, which is assumed by most models in color science.
chromaticity hue saturation chroma colorfulness purity.