[argyllcms] Re: Lost shadow detail in PS CS2 with Lab profile

  • From: Vallo Kallaste <kalts@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 27 Dec 2009 15:56:23 +0200

On Sun, Dec 27, 2009 at 02:51:35PM +0200, Vallo Kallaste <kalts@xxxxxxxxx>

> Can anybody please tell me why using the Lab cLUT display profile cause
> lost dark shadow detail? The data set for profile generation is same and
> shaper+matrix profile (colprof -as) has no such effect in Photoshop CS2.

Another data point is that the same 16bit, 2.2 gamma radial grayscale in
PS gives different black levels in the dead centre. It's K=90 for matrix
profile and K=96 for Lab cLUT profile. Should be K=100, right?  I'm
absolute newbie when it comes to color management and Photoshop, so don't
know what to expect. Should also note that using the same Lab cLUT profile
in Picture Window Pro I'm currently trying out gives better details in the
deep shadows. PWP is set to using lcms. It's really frustrating because no
matter what you read it's always written in big letters that monitor
calibration and profiling is the first and most important thing. Because
you can't edit what you can't see. True enough. But I'm losing faith
because now it seems that different CMM's can't agree even on the
grayscale. I don't want to know what could happen to colors if there are
already such grayscale discrepancies. Ugly stuff the color management is.
Not to mention that uniform gray on this Dell 3008WFP is a joke, but LCD's
and regression in consumer displays is another matter altogether. Hope
this fifty-fifty data/rant didn't get on anybody nerves. Merry Christmas
to all.
Vallo Kallaste

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