Re: Calibrating an Eizo CG21 with EyeOnePro
Re: Calibrating an Eizo CG21 with EyeOnePro
- Subject: Re: Calibrating an Eizo CG21 with EyeOnePro
- From: Roger Breton <email@hidden>
- Date: Wed, 22 Dec 2004 09:20:37 -0500
>> My EyeOnePro may be in need for a recertification but has anyone noticed how
>> the EyeOnePro "overestimates" Luminance (Y) in emissive mode? I just
>> finished calibrating my Eizo CG21 to my standard target luminance of 85
>> cd/m2 (yes, folks, I work in a cave). But a quick measurement with a freshly
>> calibrated Minolta CS-100 reveals 95 Cd/m2!? In comparison, my 5 year old
>> Mitsubishi 19" 900u reports 85 Cd/m2 on the Minolta scale.
> Ah within the scope of multiple Sequel instruments, X-Rite, and multiple
> Gretags I don't see much if any differences between the recorded results.
> At least if it's the colorimeters the have a good inter-instrument and
> inter-make agreement.
Thanks Neil. I'm not sure what is what anymore. If I use my EyeOnePro in
conjunction with the latest ColorShop X v1.4 software, which does support
the EyeOne directly now, in all measuring modes, thanks to the good folks of
Grand Rapids MI, my Eizo CG21 calibrated white point chromaticity correspond
to x=0.3457 y=0.3704 or 5037K CCT. That is good news since I am targetting
5000K. But if instead I use my EyeOnePro in conjuction with the latest
GretagMacbeth MeasureTool v5 software, using Spot measurement in emissive
mode, my Eizo CG21 calibrated white point chromaticity now corresponds to
x=0.3365 y=0.3499 or 5335K CCT. You see the difference? Same instrument, two
different software packages.
BTW, I would really appreciate if ColorShop X would NOT normalize emissive
readings to Y=100. Why can't it report the measured 'absolute' tristimulus
values? ColorShop 2.6.2 used to do that all the time with my DTP92. I drove
me mad. I had to get into ToolCrib to get the absolute readings reported by
the instrument. (Long story)
So, on the face of the above analysis, it looks like Eizo ColorNavigator v3
is receiving correct information from my EyeOnePro afer all. I was asking
ColorNavigator for 75 Cd/m2 and 5300K. And once it finished calibration, I
see now that I indeed ended up with 73.2 Cd/m2 and 5335K CCT, as reported by
MeasureTool. So, at least both ColorNavigator and MeasureTool are telling
the same "lies".
This being said, at this point, I don't know which package to believe. And I
am starting to doubt my Minolta CS-100 colorimeter fresh calibration for
which I paid an arm and leg for? Because, when MeasureTool reports X=70.4
Y=73.2 and Z=65.6 on a blank Photoshop window, while the active monnitor
profile is Eizo's, my CS-100 reports Y=84.9 Cd/m2. I know Minolta calibrates
to a Illuminant A type of light source, traceable to NIST. But can a self
luminous display radiance differ from a tungsten light source by that much?
I am going to have to talk to the good Minolta folks.
Incidently, I also in my stable of instruments I acquired over the year, an
old Minolta nt 1/3 P luminance meter (similar to the CS-100 but without
chromaticity reading capabilities). I had that one verified by the Canadian
equivalent of NIST a two years ago and they said its luminance reporting was
on par with their other instruments. Well, that unit reports 76 Cd/m2 on
that same blank Photoshop window -- about the same as my EyeOnePro.
More food for thoughts...
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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