[argyllcms] Re: Display profiling problem

  • From: Kristian Jörg <krjg@xxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 02 Apr 2012 15:50:58 +0200

I had some problems with total black crush too. I found it to be the Color management in Windows that was interfering. Control panel-> color management. There is a checkbox for "use my settings for this device". When that was checked I got the crush after dispcal had run, if I unchecked it everything was ok. The funny thing is that after I have calibrated and loaded the profile I can now set that checkbox - and use the dialog to choose which profile to use as standard.


So, this is not the complete answer, but maybe a clue where to look. There is also the advanced tab in that dialog that opens an identical dialog - now with global settings. Which is in use - maybe mr Gates knows?

/Kristian

George Pop skrev 2012-03-25 01:34:
Hello,

I am in over my head trying to solve a display profiling issue. I hope that someone more knowledgeable on this mailing list will help me.

I have a monitor (Samsung F2380) with a black crush problem that is not subtle. A lot of details in the shadows in photos and video are lost.

For a while I've used this monitor with a profile that I found on the Web. That profile has worked wonders, completely solving the black crush problem. Photos with a full tonal range can now be displayed with excellent contrast and no loss of details. But it has a color cast which I wasn't able to fix using the RGB settings in the monitor's menu.

So recently I bought a colorimeter (the Colormunki Create/i1Display2) and have used it with dispcalGUI and Argyll 1.3.6. The resulting profiles get rid of the color cast, the grays are spot-on. But the black crush problem is back.

I have tried both "Curves + matrix" profiles and "XYZ LUT + swapped matrix". On the latter, I activated gamut mapping for perceptual intent (using sRGB from Argyll as a source profile) and have successively tried "Luminance matched appearance", "Perceptual", and "Perceptual appearance" as gamut mapping intents. The "default intent for display device profile" is Perceptual, and I also made sure that my color managed apps use perceptual. The differences between these profiles are marginal as far as the black crush problem is concerned.

My calibration and profile settings are: D65 white point, native white level, native black level, gamma 2.2, high quality calibration & profile, BPC on. I've also tried native white point, gamma 2.4 (worse), 2.0 (also worse) and L* (this did open the blacks a little, but the midtones and highlights are too high).

I don't know what else to try. I've been brute forcing the calibration settings with considerable waste of time and constant disappointment.

Can any information be recovered from the profile I found on the Web to figure out what makes it work so well for tonal range?

Any suggestions would be welcome.

Thanks,

George


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