[argyllcms] Re: CRT controls

  • From: Roger Breton <graxx@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Wed, 05 Mar 2008 06:52:14 -0500

Hi Rhys,

> On an IBM P275 I have controls for contrast, brightness, individual
> RGB contrast and individual RGB brightness. Of the individual
> controls, which is equivalent to RGB gain & offset in dispcal?

Gain is Contrast. Brightness controls the black point luminance, and the
white point luminance to some extent. If you have individual RGB contrast
that's what you use to affect the color balance of your monitor -- it's
white point, how yellow or blue it is. If you have individual RGB brightness
then I'll say you have "bias" controls, and with that you can control the
"color" of the black point.

> And
> what are the best practise settings to begin tuning the calibration
> from? For example the general controls usually are max contrast and
> minimum brightness.

You need to set yourself some numerical targets. Like 90 to 100 cd/m2 for
the white and 0.30 to 1.00 cd/m2 for the black.

> On a related note, if I repeat the black level portion of dispcal it
> wants me to go lower with each iteration despite meeting it's target
> each time. Is this just trying to get to a level of 0 limited by the
> default -k factor? Is there a level I should be aiming for short of
> pure black?

I'll leave this one to Graeme...

Roger Breton 

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