[argyllcms] AW: How do I create a linear luminance LUT?

  • From: "Jens Heermann" <argyllcms@xxxxxxxxxxxxxxx>
  • To: <argyllcms@xxxxxxxxxxxxx>
  • Date: Wed, 6 Jul 2011 16:59:03 +0200

Be informed that the human eye doesn't respond linear to luminance. So
creating a calibration with a digitally linear setting (no matter if
Gamme=1.8,2.2 or 1.0) will not result in letting you perceive a linear
weighted gradient.
If you want to "see" a linear gradation between white and black, you should
use a L*-gamma-calibration, because the L*-gamma-curve is adapted to the
human perception. 

I hope that helped you a bit..

Kind regards
Jens

-----Ursprüngliche Nachricht-----
Von: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
Im Auftrag von Geoff Ghose
Gesendet: Mittwoch, 6. Juli 2011 02:09
An: argyllcms@xxxxxxxxxxxxx
Betreff: [argyllcms] How do I create a linear luminance LUT?

I apologize if this is a very basic question, but I'm really quite lost. I
want an icc monitor profile that approximates linear input to luminance.
(Yes, I realize that it can only be an approximation, and will suffer
especially at low values).

So an RGB value of 128,128,128 is half the luminance of 255,255,255. (This
are for visual psychophysics experiments).

I have tried setting target gamma to 1.0, but that really doesn't seem to do
much of anything: when I run a report on the uncalibrated and calibrated
monitors I get essentially the same gamma. My impression is that all the
calibration is doing is trying to ensure that the color temperature is
pretty consistent across input levels, but not remapping the input output
relationship so as to significantly change gamma.

What am I doing wrong?

Geoff Ghose


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