[argyllcms] Manual channel limits doesn't work in printcal for RGB-printer

  • From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 15 Nov 2009 20:17:43 +0300

V1.1.0_RC1, Windows Vista:
When calibrating an RGB-printer, it's impossible to achieve the "darkest" black 
R=B=G=0 in the calibration result if the printcal have select the other limits. 
Even if I use "-x r 100", "-x g 100" and "-x b 100" keys.
Try my printer example attached.

The workflow:

targen -v -d2 -f0 -m0 -e9 -s274 Lin
printtarg -v -ii1 -A0.6 -a0.8 -m0 -L -T360 -p240x225 Lin
chartread -v -a Lin
printcal -v -p -i -x r 100 -x g 100 -x b 100 Lin

If You try "printcal -v -p -i Lin", the curves will be the same.

If I print the next targets by printtarg with -K"Lin.cal" function, the R=G=B=0 
output TIFF level isn't achievable. So there is heavy gamut restriction from 
the black side.

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