[argyllcms] Re: DTP92 error reading black level

Hello Graeme,

After a calibration, I get:

$ dispcal -d2 -i92 -E -v
Setting up the instrument
dispcal: Warning - Unable to read or set display RAMDAC
Place instrument on test window.
Hit Esc to give up, any other key to continue:
Target white = native white
Target brightness = native brightness
Target gamma = 2.200000
Commencing device calibration
patch 6 of 6
Black = XYZ   0.00   0.00   0.00
Red   = XYZ  46.81  24.82   1.34
Green = XYZ  35.68  71.88  11.68
Blue  = XYZ  20.74   9.39  99.35
White = XYZ 104.74 108.14 115.86
Initial native brightness target = 108.140000 cd/m^2
Target white value is XYZ 104.740000 108.140000 115.860000
Target black point = nan 0.000000 nan
Gamma curve offset = 0.000000
patch 100 of 100
Verification results:
Brightness error = -1.120000 cd/m^2
White point error = 0.917289 deltaE
Maximum neutral error (@ 0.000000) = 0.000000 deltaE
Average neutral error = nan deltaE
The instrument can be removed from the screen.

The black point reading seems to be OK (0 0 0), but Target black point is 
set to nan, like the Average neutral error. Why? Is it still a reading 
error problem?

-- 
   Frédéric

   http://www.gbiloba.org

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