[argyllcms] Re: Colprof feature request: amount of black point hue correction control

Gerhard Fuernkranz wrote:


I digged out some of my old .ti3 files, and yes, this still seems to be
an issue with version 1.0.3.


Hi Gerhard,


$ colprof -v -B xxx
Total ink limit being used is 290%     <=====
No black ink limit being used
No of test patches = 750
Estimating white point
[...]


If you specified a 300% ink limit in targen,
then it gets propagated to coloprof which by default
applies the usual 10% reduction rule of thumb
to ensure that the profile is within the measured gamut,
resulting in a 290% limit.

If you don't use a reduced ink limit in the profile for CMYK,
you often get some strange looking profiles near black.

If you don't specify an ink limit in targen, then
no ink limit is propagated to colprof, and it
doesn't apply an ink limit to the profile

So all this is operating as expected, although I
would have thought a 290% RGB ink limit would affect the
white point for RGB rather than the black point.

I could automatically override the ink limit in colprof for RGB,
but I'm a bit wary of making too many special cases, since special
cases end up causing people surprises.

cheers,

Graeme Gill.

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