[argyllcms] dispcal gamma with sRGB curve
- From: Alberto Ferrante <alberto.ferrante@xxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 21 May 2011 13:54:50 +0200
Dear all,
I recently changed my colorimeter (I had a Spyder2, now I have an
Eye-One Display LT) and I am facing what it looks to be a problem.
I run dispread as I was used to:
dispcal -t6500 -gs -k0 -b 100 -q h -v -y l eizoS1961
The problem I am facing is with gamma: dispread -r measures, with the
profile obtained by using the command above, a gamma of 2.82 which is
pretty high. I have not set any ambient light adjustment, therefore I do
not understand why gamma is not 2.2 as it should be. The same command,
with the Spyder2, was giving a gamma of approximately 2.2.
The ambient light measured by argyll is approximately 14.5, but, as I
said, I haven't used this parameter.
Below the results of the calibration ad of the measurement.
Any explanation will be highly appreciated.
Best regards,
Alberto
Display type is LCD
Target white = 6500.000000 degrees kelvin Daylight spectrum
Target white brightness = 100.000000 cd/m^2
Target black brightness = native brightness
Target gamma = sRGB curve
Display adjustment menu:
Press 1 .. 7
1) Black level (CRT: Offset/Brightness)
2) White point (Color temperature, R,G,B, Gain/Contrast)
3) White level (CRT: Gain/Contrast, LCD: Brightness/Backlight)
4) Black point (R,G,B, Offset/Brightness)
5) Check all
6) Measure and set ambient for viewing condition adjustment
7) Continue on to calibration
8) Exit
Commencing device calibration
patch 6 of 6
Black = XYZ 0.08 0.07 0.10
Red = XYZ 45.94 24.35 1.57
Green = XYZ 31.27 66.04 10.72
Blue = XYZ 17.82 9.48 97.32
White = XYZ 95.46 100.43 109.58
patch 48 of 48
Target white value is XYZ 95.047834 100.000000 108.839185
Adjusted target black XYZ 0.08 0.07 0.10, Lab 0.63 0.35 -0.30
Target black after min adjust: XYZ 0.075 0.070 0.098, Lab 0.635 0.349 -0.303
Gamma curve input offset = 0.000000, output offset = 0.000702, power =
0.000000
Viewing conditions adjustment aprox. power = 1.274936
Total Iteration 2, Final Samples = 32 Final Repeat threshold = 0.900000
Creating initial calibration curves...
Doing iteration 1 with 16 sample points and repeat threshold of 1.272792 DE
patch 16 of 16
Brightness error = 0.022459 cd/m^2 (is 100.022459, should be 100.000000)
White point error = 0.109939 deltaE
Maximum neutral error (@ 0.295400) = 1.129951 deltaE
Average neutral error = 0.599001 deltaE
Number of measurements taken = 24
Computing update to calibration curves...
Doing iteration 2 with 32 sample points and repeat threshold of 0.900000 DE
patch 32 of 32
Brightness error = -0.070820 cd/m^2 (is 99.929180, should be 100.000000)
White point error = 0.168525 deltaE
Maximum neutral error (@ 0.801684) = 0.833734 deltaE
Average neutral error = 0.460123 deltaE
Number of measurements taken = 39
The instrument can be removed from the screen.
Written calibration file 'test.cal.cal'
Current calibration response:
Black level = 0.08 cd/m^2
White level = 100.24 cd/m^2
Aprox. gamma = 2.82
Contrast ratio = 1263:1
White chromaticity coordinates 0.3125, 0.3289
White Correlated Color Temperature = 6518K, DE 2K to locus = 4.7
White Correlated Daylight Temperature = 6518K, DE 2K to locus = 0.1
White Visual Color Temperature = 6350K, DE 2K to locus = 4.5
White Visual Daylight Temperature = 6515K, DE 2K to locus = 0.1
The instrument can be removed from the screen.
--
Home page: http://www.alari.ch/people/alberto
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