Color quality is a function of the spectral output of a light source, the spectral absorbance/reflectance of an object, and the sensitivity of the eye’s cone photoreceptors to different wavelengths of light, which we perceive as color. Color quality impacts visual appeal and can either
contribute to or detract from occupant comfort. Poor color quality can reduce visual acuity and the accurate rendering of illuminated objects.
For instance, foods, human skin tones and plants may appear dull or unsaturated under lights that have low color quality metrics. Color
rendering index (CRI) is a common way to measure color quality, capturing R1-R8 metrics. R9, while not always reported, is also included
as part of this feature, as R9 values further take into consideration how we perceive the saturation of warmer hues.