1.1 ,This guide is intended for use in establishing the operating characteristics of a visual display unit (VDU), such as a cathode ray tube (CRT). Those characteristics define the relationship between the digital information supplied by a computer, which defines an image, and the resulting spectral radiant exitance and CIE tristimulus values. The mathematical description of this relationship can be used to provide a nearby device-independent model for the accurate display of color and colored images on the VDU. The CIE tristimulus values referred to here are those calculated from the CIE 1931 2°, standard colorimetric (photopic) observer.