[argyllcms] Re: Displays with internal gamut emulation

  • From: János, Tóth F. <janos666@xxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Fri, 20 Aug 2010 16:30:12 +0200

> You own the Dell U2410

Have you read the Prad.de review?
> I remember there is a problem with the custom mode that defeats a
> good calibration.
>

Yes, and no. I already consulted with the author of that review and I also
made a lot of measures on this display to make out it's behavior.

You can find my charts here. (Yes, these supposed to be in a "review". I
canceled it until the new ArgyllCMS version arrives, but the text has been
written in hugarian language anyway...)



> Which is the best mode to calibrate Dell U2410?

Display mode or sensor mode?

I think the sensor should be in Adaptive HighRes mode. (And you should wait
for the 1.2.2 version as well.)
The display mode depends on your needs.

If you want to work with sRGB or AdobeRGB color spaces, I recommend you to
choose one of these modes. (If you are not sure, then you want the sRGB mode
:D)

If you need the widest available gamut or you want to do the gamut emulation
with software CMS (which is tricky with movies and impossible with games)
you should choose the Standard mode.
But the display controller works with 12/color precision, so you don't want
to do this correction with softwares when you work with 8 bit/color
framebuffers. (Professional VGAs with 10 bit/color framebuffering and 10 bit
compatible softwares should be reconsidered.)

Either ways, I recommend you to check your factory menu first! It looks like
a mess. Only the Standard mode works with a relatively good contrast ratio
(the highest RGB Gain is 255) but it is calibrated to a strange white
temperature (with the Gains). The sRGB and AdobeRGB modes were cut to work
with lower contrast ratios (the highest Gains are much lower than 255 - They
had the reasons to do this but you can do it better...)

So, you may want to take a picture of the factory settings (as a backup) and
set everything to 255-255-255 with a DeepColor compatible VGA and let the
software to calibrate the display with effectively 10 bit/color VGA LUT.
Or you may want to use these Gains to set the white temperature (starting
from 255-255-255) to the desired value for the Standard mode.
I think you won't be lucky with the sRGB mode Gains because the RGB Level
graphs are crossing each other, so you can't set the white balance with
gains in this mode. (But you should check it for yourself with a test
calibration: full 255 values and you will see if the LUT curves are crossing
each other or not.)

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