[argyllcms] Re: Possible bug in gamut mapping in collink
- From: "Lorenzo Ridolfi" <lorenzo@xxxxxxxx>
- To: <argyllcms@xxxxxxxxxxxxx>
- Date: Thu, 4 Dec 2008 19:17:24 -0200
Ok, Thank you. I assigned eci-RGBv2 to the original image and the "black
hole" vanished in the converted image.
Best regards,
Lorenzo
-----Original Message-----
You've got a synthetic source image that occupies the surface of the ROMM
colorspace, so many of the source colors you are trying to gamut map fall
outside the spectrum locus, are therefore imaginary.
By default Argyll uses CIECAM02 as a gamut mapping space, because
of its ability to accommodate viewing condition adjustments, and its
handling of hue mapping (blues not turning purple etc.), but one of
the issues with CIECAM02 is that it is only defined for
real world colors, and in fact is numerically undefined for
imaginary colors. The blue colorant of your image is imaginary,
and the problem you noticed is the result of how my implementation
of CIECAM02 handles values that are not defined in CIECAM02 space.
[ Many other implementations will fail in much more spectacular ways
than this. ]
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