The article White Light by Mark Rea and Jean Paul Freyssinier is summarized and discussed. The measurement procedure is very promising, and could lead to a variety of significant measurements. However, some of the interpretations presented are problematic. The measurements were based on loci of equal correlated colour temperature, which have neither precise nor consistent physiological or perceptual interpretations, and the resultant conclusions are therefore not uniquely meaningful. Nevertheless, the measurement technique could easily be adapted to slightly different methodologies that could be very powerful, and such replication is highly recommended. (c) 2012 Wiley Periodicals, Inc. Col Res Appl, 2013