[argyllcms] Re: Cannot get calibration/profiling to yield good results, user error?

  • From: Leonard Evens <len@xxxxxxxxxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 31 Dec 2008 10:27:08 -0600

On Wed, 2008-12-31 at 14:46 +0100, Karl H. Beckers wrote:
> Hi all,
> 
> I'm struggling with this display calibration/profiling exercise.
> I have calibrated and created a profile with dispcalGUI using the
> display's native whitepoint, target brightness of 100, gamma 2.4
> (lcd-t-b100-g2.4-f0-k0-qhh-lut). When I load this with -I and -L colours
> are much improved. I look at this:
> http://www.fc-prints.de/fileadmin/daten/fcPrints_Testbild_100ppi.jpg
> 
> And I can see both the dark and bright "1" in the image, the colors in
> the flower and the parrot are very natural and strong in the center
> (apple and such).
> When I load the icc profile in Gimp, select color corrected display, and
> open the same jpeg in Gimp, the colors are way to saturated. The red in
> the flower's leaves loses nearly all of its contrast and becomes a shiny
> red blur.
> 
> What's wrong here?
> 
> - Am I supposed to load the profile in gimp? Or do I only do one of the
> two: either dispwin OR gimp color mgmt?
> - I noticed that with dispcalGUI, the profiling part is done with
> calibration already loaded? Is that the right way to do it?
> 
> I have the gut feeling that I'm correcting twice here, but don't quite
> know where to look.
> 
> TIA,
> 
> Karl.
> 
> 

I am not familiar with dispcalGUI.  I just use the command line version
of argylcms, under Linux.   I think others who are much more
knowledgeable than I will respond more fully, but let me make a stab at
an answer. But you should take it with more than a grain of salt.

It sounds as if the calibration part which involves a look up table
loaded in your video card is doing a decent job, but the profile used by
gimp is then messing things up.  If I understand these things correctly,
it doesn't matter how many times you load the look up table, you always
get what you just loaded.  The previous one is written over.  I don't
think your problem is that something is being doubly corrected, but more
likely that you profiling was not done correctly. 

You should give more details, e.g., your operating system, your type of
monitor, which version of gimp you are  using, etc.

I noticed that when I opened the test image, which I saved from firefox,
in gimp, I was queried about whether or not I wanted to use the embedded
profile as my working space.  In my case, it didn't seem to matter a
whole lot which I chose to do.  But which choice did you make?   If you
weren't queried, you may have reconfigure gimp preferences to query
you. 

You can also try other applications which  use color management.   Eye
of Gnome is one such.  Another I've had good luck with is inkscape.


-- 
Leonard Evens <len@xxxxxxxxxxxxxxxxxxxxx>
Mathematics Department, Northwestern University

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