[argyllcms] Re: Eye-one and DTP94 using dispcal
- From: Graeme Gill <graeme@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 12 Aug 2008 13:43:12 +1000
Martin Weberg wrote:
To me a difference of 45 cd/m^2 between instruments is too big, Is there
anything I could try to get more info on the instruments or the operation?
I agree it's large, but that just seems to be the way it is. The origin
of the i1display and i1pro is different (different manufacturers),
and this may be reflected in different calibration standards.
Note also that the disagreement between the instruments may not
even be consistent, since the measurement geometry may
vary (ie. the instruments sensitivity to light coming
from different directions), as well as the spectral sensitivity
being not quite standard observer for the colorimeter.
Here's what I get using an "A" type spectral source,
with a fairly broad light distribution. Note
there is some instrument positioning error and
source variation error in the readings:
Argyll GM driver
Eye 1 pro rev. D 1214.07 1214.98
Eye 1 pro rev. A 1132.49 1134.57
Eye 1 display 2 LCD 976.10 972.50
Eye 1 display 2 CRT 915.85 912.15
So I don't think there is anything fundamentally wrong
about the Argyll driver. I'm not sure if (say) other software
has a fudge factor that brings compensates for the instruments
different calibration factors. While it's easy enough
to concoct a fudge factor for a particular display and two
particular instruments, it's not possible to know how
representative such a factor is for other light sources
and other instrument instances.
Graeme Gill.
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