[argyllcms] Re: Gamut mapping not-monotonic

Vittorio Villani wrote:
The BW seems to be more problematic.I made some measurement with the ColorMunki 
(same
hardware used for the profile). I did 3 measurements for each value to be sure 
that the
reading was correct. I will report the medium value.

For black point (L*a*b* values in the file 0 0 0) I have an a* value of about 
-1; L*and
b* are close to what I expected (4,2 and -0.2). For a grey point (L*a*b* values 
52 0 0
0 in the file) I have 48.9 -0,8 -0.6. So what it seems that BW is a little bit 
green
and not neutral.

That's a delta E of 1. That's pretty good. Many would say it is excellent.

In any case, the neutrality will be judged visually in comparison to the
paper white. What is the paper a* b* ?

How are you testing it ? If you are measuring it and using the measurement 
values,
then you need to be feeding your target L*a*b* values into the absolute 
colorimetric
B2A table. Naturally you won't get the target values if they are out of gamut.
Is that what you're doing ?

Graeme Gill.

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