CMC Delata E 2:1 is an improved color difference metric based on
the CIE Delta E 76 metric
developed in 1984 by the Colour Measurement Committee of the
Society of Dyers and Colourists. It has two parameters lightness
(l) and chroma (c), with the 1:1 being the threshold of
imperceptibility, and the 2:1 values being those for for
acceptability.
Since it is based on L*a*b* space, a reference white needs to be
chosen to compute this Readout value.
Details of white point
configuration.