[argyllcms] Re: Calibration issue with colormunki

  • From: Juergen Lilien <jp.lilien@xxxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 21 Nov 2010 21:57:49 +0100

Hello Emmanuel,

Emmanuel Michonneau wrote:

> Why response curves of colormunki does not start to zero?

Maybe the black point of your monitor has a slight color cast, or there
is a problem with temperature related black point drift of the Colormunki.

It is a good practice to give the Colormunki some time at the screen
(even an hour is not too long, if you are very demanding/critical) to
acclimatize to the screen temperature, before starting the measurements.
You can also try to enable the black level "drift compensation during

This brings me to the point, that you should tell us about the
calibration and profiling settings you use in dispcalGUI.

Have you tried the dispcalGUI "Verify profile" function (tools menu) to
check the calibration/profile?

> To illustrate my problem here are 3 screenshot of the same photo with
> respectively :
> - no profil : http://emmanuel.michonneau.free.fr/pub/withoutprofil.jpg
> - Spyder profil : http://emmanuel.michonneau.free.fr/pub/spyder_argyll.jpg
> - Munki profil :
> http://emmanuel.michonneau.free.fr/pub/colormunki_argyll.jpg

There are still deep blacks (0,0,0) in the Colormunki sample, so it
seems to be a different gamma correction applied, but the picture does
not look necessarily bad to me.

Maybe it is better to compare a more artificial picture, have a look at:


> Does the problem comes from my display and its TN panel?

The 8 Bit (per channel) color resolution is only archived with a FRC (in
the time domain) dithering stage, so it should be better to enable the
adaptive mode to use the longest possible integration time.

By the way, have you disabled the ambient light sensor of the monitor?

Best regards, Juergen

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