Re: GRACoL & SWOP Tolernaces
Re: GRACoL & SWOP Tolernaces
- Subject: Re: GRACoL & SWOP Tolernaces
- From: Uli Zappe <email@hidden>
- Date: Fri, 25 Apr 2008 13:10:02 +0200
Am 25.04.2008 um 03:10 schrieb Roger Breton:
To your knowledge, are the results obtained through PatchTool's
IDEAlliance
monitor certification procedure comparable from one instrument to
the other?
I know this is the 10 million dollar question but you opened the
door ...
For what it's worth, comparing (as good as possible) the absolute
precision of the various available measurement devices was a central
part of the big review I told I've been writing. From the results I
got, and given the tolerances that you discuss, I very much doubt it's
comparable for the majority of the available instruments.
Personally, I had 3 instruments each at my disposal of the following
models: i1Pro, i1 Display and Spyder2. I only had 1 Spyder 3 as this
was released only shortly before the end of the test runs, 2 DTP94 as
these are becoming rare, and 1 huey pro (as I figured that would be
sufficient). I also could cross-check with more than 20 additional of
these instruments and a Minolta CS1000 spectroradiometer that were
evaluated by the Fogra at the Print Media Production Forum 2007 in
Stuttgart/Germany (www.pmpf.de, http://forschung.fogra.org/index.php?menuid=62&downloadid=83&reporeid=123)
. I also performed a 6-months repeatability test (again, apart form
the Spyder 3 that wasn't available yet at the beginning).
I can't write down all the details here, but for a short impression,
I'll give you the summary result for display measurements. Note that
these are not deltaE values, but "scaled" deltaE values, i.e. the
deltaE values of the various test disciplines are each divided by the
limit value recommended by the UGRA. Therefore, you can easily average
the various test disciplines without undue distortion. 1 always equals
the recommended UGRA maximum, results > 1 are beyond the UGRA limit.
Also note that these values are averages of all possible combinations
with the various measurement software packages available. Sometimes,
there are remarkable differences between specific combinations; for
instance, both the Spyder 3 and especially 2 achieved better results
with basICColor display than with the corresponding Spyder software.
That being said, here are the results:
Device scaled scaled
deltaE deltaE
mean max
DTP94 0.47 0.67
i1 Pro 0.56 0.75
Spyder 3 0.74 1.33
huey 1.19 2.80
Spyder 2 1.56 3.18
i1 Display 1.89 5.34
Some remarks: the i1 Display devices performed horrible; I would
consider them pretty much unusable for any serious task. There's not
even decent repeatability (especially after 6 months) or inter-
instrument agreement. Why X-Rite stopped the DTP94 (the best
performing instrument of all) in favor of the i1 Display after the
merger with GMG is completely beyond me.
The Spyder 2 is at least internally consistent; inter-instrument
agreement and especially repeatability were good.
The huey got the white point completely wrong (dE(76) 5.6); as a
result, its profile made the display look much worse than the above
values suggest. But apart from that, it's surprisingly decent.
I have no experiences with the long term repeatability of the Spyder
3, but if there are no bad surprises here, this currently seems to be
the only colorimeter runner-up for the DTP94. Its software has issues
with dark colors though; use basICColor display instead for the time
being.
The DTP94 was definitely the best instrument; metrological as well
visually; the i1Pro did not deliver results of the same delicate
smoothness (unless used with ProfileMaker, which unfortunately had
other issues), but is fine metrological.
All tests were performed for D65, max luminance, min black - and gamma
1.8 ;-)))
Bye
Uli
________________________________________________________
Uli Zappe, Solmsstraße 5, D-65189 Wiesbaden, Germany
http://www.ritual.org
Fon: +49-700-ULIZAPPE
Fax: +49-700-ZAPPEFAX
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