In this paper we compare the merits of two standards for the correlated color temperature of reference white for video display units, one standard at 6500 K and the other at 9300 K. The choice of 6500 K evolved from the N.T.S.C. specification for studio television receivers based on Illuminant C -- an "average daylight." The assumption of the N.T.S.C. was that, if equal-signal white is made to have the chromaticity of a reference illuminant, then colors rendered by the television systems should approximate the colors actually seen under the reference illuminant. Given this assumption, average daylight seemed to be the most natural adaptation state and hence acceptable for a white point. On the other hand, many manufacturers of home television receivers and VDU graphics displays chose 9300 K because the visual efficiency of the prevailing blue phosphors was greater than that of red or green phosphors, because viewers did not object to a blue color bias, and because 9300 K was bluer than any of the prevailing ambient illuminations. In the years since the original adoption of the 9300 standard, these facts underwent some change, suggesting a re-evaluation of the 9300 K standard.