Re: Calibration targets for scanner / Calibration of CUPS color laser printer

[Richard Hughes <hughsient gmail com>]

2010/9/26 Jean-Michel Pouré - GOOZE <jmpoure gooze eu>:
> 1) ICC database available?
> I would like to know whether there is a free (as in Free Software)
> common database of ICC profiles available.

http://github.com/hughsie/shared-color-profiles is a repo of common
profiles you'll probably find useful in day-to-day work, e.g. Adobe
RGB profile and sRGB profile, and a few print profiles.

There's not a lot of point getting a big database of user-submitted
profiles as devices change over time, and were made using different
methods. Your LG 21W TFT screen might have been made in Malaysia in
2008, mine might have been made in China in 2009. Yours is older, and
so is more "yellowy" than mine. Etc.

Using a 80% correct profile is probably not a good idea.

> 2) Scanner calibration target
> I would like to buy a scanner calibration target. Some cheap ones are
> available on http://www.targets.coloraid.de. But there are so many I
> don't know which one to buy. Can you give some advice?

I use the R1 Wolf Faust IT8.7 target. Wolf is a dude.

> 3) Laser calibration / CUPS
> I wrote an email on CUPS to ask whether CUPS supported calibration and
> the answer was no. CUPS does not yet support ICC profiles.

Well, it kinda does. Ish. Depends.

Apple wrote a lot of the framework code for OSX, and for Linux a lot
of the code is #ifdef 0 //FIXME, which is a technical way of saying it
doesn't work. That said, ghostscript in svn trunk has more complete
color management support, and so it shouldn't be too long before
support filters down to distros.

> My printer is a Lexmark c720, an old color laser printer, but with very
> cheap cartridges on eBay. I find the colors a little bit dull and I
> imagine it could improve with calibration.

Sure, of course.

> The Lexmark c720 has an auto-calibration feature. It supports 4 or 5
> color presets available from the PS driver, which is very vague.

Right, I would be very wary of any "auto_calibration" feature.

> How can I dig into this driver and try to calibrate output? Do you think
> it is possible to create ICC profiles for the 4 or 5 printer presets? Is
> it possible or is there no way to reach a solution?

I think with a device like a ColorMunki it's certainly possible.

Richard.