[argyllcms] Re: RGB Printer profiling and ColorSavvy CM2C

Roger Breton schrieb:

Does Argyll have to generate the target itself,

Argyll has to generate the target, no question.

Not necessarily, if you manage to create the .ti3 file somehow manually (e.g. with your own tools, or with the logo2cgats utility, which converts GMB measurement files to .ti3 format, or howsoever). In order to create the profile, you ONLY need the .ti3 file, containing both the device values and the colorimetric/spectral measurements of the patches.

Nevertheless, IMO targets generated by Argyll, especially if they have been created for a particular device ("targen -c profile.icm ..."), give higher overall characterization accuracy, with a lower number patches, than other targets with a fixed layout. IMO an Argyll generated target with 1500 CMYK patches outperforms e.g. the ECI target, which has approx. the same number of patches. 

What I'd like to do is use a sparse scattering of patches, and then
augment this in the "difficult" areas, adding some extra patches down
the grey axis and in typical skin tones.

Hmmh, I'm not sure argyll can do that. Graeme?

You can add additional measurement manually to the .ti3 file - no problem. And you can obviously even increase the weight of particular measurements by adding them multiply to the .ti3 file. But at present there is no tool to assists this task.

You can e.g. also create a .ti1 file manually, containing only the patches you want to augment, print this augmentation target as usual with "printtarg ...", and measure it in order to create a .ti3 file. Then you add the measurements from this .ti3 file to the original .ti3 file manually with a text editor, and recreate the profile.

For example, to create the contents for the table in the .ti1 file to augment patches along the gray axis for an RGB device you could do something like

   $ perl -e 'for $i (20..99) { print "$i 0 0\n" }' |
   xicclu -pl -ir -fif profile.icc |
   awk '{ print $8, $9, $10 }' |
   icclu -px -ir -ff profile.icc |
   awk '{ print ++i, 100*$1, 100*$2, 100*$3, 100*$8,100*$9,100*$10 }'

Regards,
Gerhard




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