[argyllcms] Gamma problems

  • From: David Garabana Barro <david@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Mon, 9 Nov 2009 01:34:50 +0100

Hello, everyone

I'm having a problem calibrating my CRT (NEC FE950) with ArgyllCMS running on 
Debian and a xrite i1 Display 2, which is driving me really crazy

I'm targetting for a gamma of 2.2, but no matter how I create the profile, I 
allways end with much higher (~ 2.8-2.9) gamma. 

I cannot realise what am I doing bad. I have tried lots of different options, 
qualities,  I have read almost all documentation I found about monitor 
calibration and argyll, I have even tried with dispcalGUI, but no matter what 
I try, I never get (even close to) 2.2 gamma. 
I have spent several days with this matter, with no success.

Desperate, I have installed Windows and xrite's software on an old HDD. To my 
astonishment with only one try, I have obtained a profile which "dispcal -yc -
r" says is 2.2 gamma. I have also confirmated this with several visual gamma 
checkers.

Any clue on what should I doing bad?

PS
This is the output of dispcal -yc -r. First one is with one argyll profile 
loaded. Second one is xrite's Match profile created on windows.

XRandR 1.2 is faulty - falling back to older extensions
Place instrument on test window.
Hit Esc, ^C or Q to give up, any other key to continue:
Current calibration response:
Black level = 0.08 cd/m^2
White level = 91.03 cd/m^2
Aprox. gamma = 2.84
Contrast ratio = 1076:1
White chromaticity coordinates 0.3154, 0.3191
White    Correlated Color Temperature = 6427K, DE to locus =  4.8
White Correlated Daylight Temperature = 6433K, DE to locus =  8.6
White        Visual Color Temperature = 6629K, DE to locus =  4.6
White     Visual Daylight Temperature = 6847K, DE to locus =  8.2
The instrument can be removed from the screen.

-----------------------------------------------------------------------------------------------

XRandR 1.2 is faulty - falling back to older extensions
Place instrument on test window.
Hit Esc, ^C or Q to give up, any other key to continue:
Current calibration response:
Black level = 0.06 cd/m^2
White level = 93.00 cd/m^2
Aprox. gamma = 2.21
Contrast ratio = 1632:1
White chromaticity coordinates 0.3114, 0.3179
White    Correlated Color Temperature = 6675K, DE to locus =  2.9
White Correlated Daylight Temperature = 6681K, DE to locus =  7.0
White        Visual Color Temperature = 6799K, DE to locus =  2.8
White     Visual Daylight Temperature = 7025K, DE to locus =  6.7
The instrument can be removed from the screen.


Thank you very much

-- 
David Garabana Barro
jabber & google talk ID:        david@xxxxxxxxxxxx
Clave pública PGP/GPG:          http://davide.garabana.com/pgp.html

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