scope:

This evaluation method is applicable to light sources and lighting systems intended for general illumination of indoor spaces and some outdoor settings, at light levels where photopic vision is dominant. It is best suited to characterize nominally white light sources (i.e., those that fall on or near the Planckian locus). If a light source's chromaticity falls outside of the chromaticity bins defined in ANSI C77.388-2017,²⁸ then calculations based on this TM should be interpreted with caution.