[argyllcms] Re: True Separation and TAC for icclink

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 20 Nov 2005 15:11:48 -0800



Burckhart Seifert wrote:

$ icclink -v -l280 -G -i4 -c0 -d0 -kt ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=100.00 M=40.00 Y=33.33 K=100.00


$ icclink -v -g -l280 -i4 -c0 -d0 -kt ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=97.33 M=65.27 Y=53.91 K=99.88


$ icclink -v -g -kt -l280 -i4 -c0 -d0 ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=97.33 M=65.27 Y=53.91 K=99.88


$ icclink -v -g -kt -l280 -i4 ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=96.93 M=65.71 Y=54.23 K=99.74

$ icclink -v -g -l280 -i4 -kt ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=96.93 M=65.71 Y=54.23 K=99.74

$ icclink -v -g -l280 -i0 -kt ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=99.22 M=64.70 Y=52.46 K=99.97

$ icclink -v -g -kt -l280 -i0 ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=99.22 M=64.70 Y=52.46 K=99.97

$ icclink -v -l280 -i0 ISOcoated.icc ISOuncoated.icc ISOlink4.icc
==> C=76.32 M=67.87 Y=57.39 K=83.18

You should test inputs 0,0,0,0 and 0,0,0,0.5 (0,0,0,50 if you insist on using something other than icclu) etc. to see what's going on. If you do, you will see that the black intent is being passed through.

For 0,0,0,1 you are noticing that:

        1) Color reproduction has higher priority than black generation
and     2) The source black is out of gamut for the K only destination, hence
           the use of CMY to reach the the target color.

If reproduction of the color is not your highest priority, then currently
icclink is probably not the tool you are looking for ...

Graeme Gill.



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