[argyllcms] Re: Gamut mapping not-monotonic
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Wed, 08 Dec 2010 19:23:13 +1100
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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