Stephen T wrote: > Both of the above are consistent but colprof's delta E values are different > and do not match > DE76 and DE94 either. Hi, do you have a specific example ? > Which delta E is colprof reporting? The documentation states only that "a > summary of the average > and maximum Lab delta E's will be printed out if this flag [-y] is set". There is no qualification, so this is plain delta E (ie. Euclidean distance). It's open source, so you can always look at the source code... > Is colprof applying any weighting to the DE00 calculation: KL, KC, KH not > equal to 1.0? Again, it's open source - it's easy enough to check, and it's noted in the source that the equations are taken from: "The CIEDE2000 Color-Difference Formula: Implementation Notes, Supplementary Test Data, and Mathematical Observations", by Gaurav Sharma, Wencheng Wu and Edul N. Dalal, Color Res. Appl., vol. 30, no. 1, pp. 21-30, Feb. 2005. Graeme Gill.