Dear Argyll team,
I use last version of Argyll together with LittleArgyll tool and manually
inserted arguments under Windows 10 64-bit Home. And I find that Argyll makes
RGB targets for Windows printer inproperly, especially for calibration. Manual
pages describe that RGB is transformed to CMY here, i.e. without K. Right, I
get graded CMY target for calibration. But if I add K patches, this doesn't
influence on calibration curves as the algorythm doesn't use K channel here.
The result is uneven K ramp on final IT8 print: dark areas are totally black,
white is grey enough. Of course, this happens with third-party inks on cheap
enough photo paper, but I get out more of this paper after manual settings
tuning. It's an obvious thing that for RGB printer colors should be converted
to full CMYK using some law, maybe using some pre-conditioning profile like
FOGRA ones. And then make upside down step for drawing calibration curves. But
now I find that Argyll doesn't have right tool to make it properly, so I ask
you to do it. I also note that target generation for RGB printer is always
uneven, it lacks of many dark patches by default and it is difficult to correct
the spread with arguments.
With regards,
Aleksei Korobov,
Yekaterinburg, Russia
