[argyllcms] Re: How is delta E calculated in colprof?

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 19 Jul 2012 23:53:56 +1000

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.

        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). 
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.

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