[Digikam-users] Re : Choose another ICC profile for converting pictures

[Remco Viëtor]

On Friday 07 October 2011 11:59:19 sleepless wrote:
> Hi Remco,
> 
> Could you explain this to me this:
> If I print from native Windows 7, or from windows XP in Virtualbox on
> Linux or from Ubuntu, and in all setups choose the same colorspaces, and
> the same paper and no corrections or whatever I get tree different prints.
> The only decent prints I get without heavy color adjustments on the
> source is in my windows 7 setup, (exactly there where I not want to be)
> with native canon printerdriver.
> I lost sofar about 50 A4´s testing for a good result on Ubuntu with
> Turboprint.
> Is this the proof that different  software interpreted color profiles in
> there own way, and thus the faillure of colormangement?

First, I don't print at home, the few I need are better done by a local 
shop....
And no, I don't think the colour profile is interpreted differently (as the 
profile only says 'for color (A,B,C) use colour (A+a,B+b, C+c)' )

That said, there's a number of factors influencing colour reproduction on an 
inkjet printer: paper type, inks used, amount of ink used, etc. As with a 
screen, if you change any of these factors, you'll have to adapt your profile. 
And I bet Ubuntu doesn't use the same driver as windows (so amount of ink used 
per dot can very well change). The problem here is that you might not apply 
any corrections, but the drivers will have to send certain settings to the 
printer. If these differ between drivers, you're out of luck.
Or you have to start profiling your printer/paper combination, which requires 
a different spectrophotometer than for screen profiling (and those aren't the 
cheapest either). 
Final solution:
Have a profile made to order:
 - download a test image (colour patches of known hues)
 - pick the settings and paper you want to use, 
 - print the test image, 
 - send  it to the provider of the test image, who will create the profile and 
send it to you (against payment...). Have a look in Google ;)
Once again, such a profile is valid for ONE printer/paper combination, with 
ONE set of driver settings. Change anything, and you'll have to get another 
profile... (same as for screen: change any setting there and you'll have to 
reprofile)

> BTW In Ubuntu systemwide color mangement does not work at all here, no
> matter which profile I choose, the colors on the monitor never change.

Sorry, I'm purely an OpenSUSE guy, can't help you there. But have a look at 
the argyllcms suite, their docs might help.

To finish, some links colour management: 
* - http://www.printerprofiling.com/index.html
* - http://jcornuz.wordpress.com/2007/12/06/printing-3-printer-color-
management/#more-175 (fairly old, but has the basics)
* - http://en.wikipedia.org/wiki/Linux_color_management (mainly concerned with 
display profiling)

Hope this helps clarifying things a bit...