[argyllcms] Re: something wrong in my workflow?

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 31 Dec 2009 11:18:20 +1100

Davide wrote:
Hello,  I got this message creating  icm form my laptop LCD,
I used this targetgen to create a large patchset (2000) and now using colprof with this arguments

colprof.exe: Warning - Values clipped in setting A2B LUT!
*** Try switching to XYZ PCS ***

It's a hint that perhaps your monitor is out of gamut of the Lab
PCS encoding range. I'm not convinced that the warning is 100% reliable
though, so I've put a more specific test in the next release,
and increased the level of information.

You can check by looking up the primary chromaticities
of the matrix version of the profile (colprof -as) and see if they
are clipped.

[ ie. iccdump -v3 -trXYZ -tgXYZ -tbXYZ profile.icm
 and check if the a or b values are outside the range
 -128 to +128 ]

Or you could use icclu on the Lab PCS cLUT profile to see if the primaries
are clipped:

   icclu -ff -ir profile.icm
   1 0 0
   0 1 0
   0 0 1


Graeme Gill.

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