[argyllcms] Re: Fluorescence

  • From: Gerhard Fuernkranz <nospam456@xxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 29 Aug 2005 00:38:26 +0200

Graeme Gill schrieb:

Gerhard Fuernkranz wrote:

Btw, Graeme, is there a reason why the default for the observer CMFs is not 1931_2, but J&V 1978_2? IMO the ICC requires measurements with the 1931 2° observer CMFs.

Not really, just that the J&V 1978_2 is mean to be the "fixed" version
of the 1931_2 data. See page 5 of Mark Q. Shaw's thesis "Evaluating the
1931 CIE Color Matching Functions" <http://www.cis.rit.edu/mcsl/research/mshaw/CMF_Thesis.pdf>

Many thanks for the interesting link. I must admit, so far I have not concerned myself with the issue "accuracy of observer CMFs". Afer looking at this article, I am somewhat distressed. Are the various observer CMFs really unable to explain/predict a metameric match better than with an accuracy of circa 4 dE_a*b* average? This sounds nearly hopeless. How should we be able to achieve an accurate metameric color reproduction under this circumstances, by profiling devices via measurements? We care much about things like profile fitting accuracy, FWA, etc., try to eliminate each thenth dE if possible in this areas - and actually we do have a significant error source directly "at the roots", i.e. at the observer CMFs, and their variability? Hmmm ...

Regards,
Gerhard



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