[argyllcms] Displays with internal gamut emulation

  • From: János, Tóth F. <janos666@xxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 18 Aug 2010 00:21:53 +0200

Some of the Dell UltraSharp displays (like U2410, U2711, U3011, etc) offers
emulated gamut modes (they can internally simulate sRGB or AdobeRGB from the
WCG-CCFL gamut).
They behaves like the EZIO CG243w but Dell doesn't offer any calibration
software which wold be able to fine tune these factory calibrated LUTs. So,
I have to fine tune these modes with my VGA LUT.


But every calibration process starts with the measurement of the primary
colors. And they will fluctuate around the black point. It is not a big
problem alone, but the white balance will be missed by the calibration
softwareB

So, I am puzzled:
I can't calibrate any other display modes with my usual targets (gamma 2.2,
D65) because the native gamut modes measure around gamma 1.7 (I will lose a
lot of contrast ratio) or they have other (various and heavy) defects.
The only way is to calibrate a factory-calibrated display mode but they work
with gamut emulation as well (they measure close to gamma 2.2 with
acceptable contrast ratio).

But the white balance is not correct in the range where the factory
calibrated gamut emulation fluctuates (it is a limitation or a defect of the
factory calibration, I guess - but it won't be a problem alone).

So, I don't know what should I do.

I can see two solutions:
- Get access to the internal LUTs (unofficially ; I guess they work just
like the CG234w)
- Reconsider this usual calibration process. (Get rid of the 100% R G B
measurements, or do more of them, I don't know.)

By the way, I have a ColorMunki Photo. (So, the last bugfix was nice. I like
this software very much now.)

Here is an example of the fluctuated saturation:
Custom mode: http://img12.tar.hu/janos666/img/82802527.png
sRGB mode: http://img12.tar.hu/janos666/img/82802793.png

And a measurement of the white stability:
Standard mode: http://img12.tar.hu/janos666/img/82802799.png
sRGB mode: http://img12.tar.hu/janos666/img/82802795.png

Other related posts: