scope:

This standard specifies a Reference White signal, and the absolute luminance level and chromaticity, including tolerances, that is to be produced by an HDTV display reproducing such a Reference White signal conforming to the encoding specifications of SMPTE ST 274 or SMPTE ST 296. The reference white level and chromaticity defined herein are intended for critical viewing in a controlled environment. They are not appropriate for some applications, such as displays used on a studio floor or in bright ambient light.