Re: Camera profiling with ICC et al
Re: Camera profiling with ICC et al
- Subject: Re: Camera profiling with ICC et al
- From: MARK SEGAL <email@hidden>
- Date: Mon, 15 Sep 2008 16:46:51 -0700 (PDT)
Uli,
Some of today's emails have really been very informative, and I'm beginning to wonder based on what I'm reading whether chasing after "accurate" profiles may be akin to nailing jelly to a wall. If there's so much difference between the spectral response of alot of real world subject matter one photographs and that of the targets one uses for profiling, it isn't entirely clear - unfortunately - that your otherwise logical inference (last sentence) would necessarily hold in practice, much as one may be attracted to a "correct according to the target" colorimetric approach.
Mark
----- Original Message ----
From: Uli Zappe <email@hidden>
To: email@hidden
Cc: email@hidden
Sent: Monday, September 15, 2008 4:45:06 PM
Subject: Re: Camera profiling with ICC et al
Am 15.09.2008 um 19:55 schrieb email@hidden:
>> I found a very high correlation between the metrologically best
>> profiles and the ones that produced the most realistic (not
>> necessarily most pleasing) image variants.
>
> Yes, that can well be true when all the errors are relatively large,
> or in any one or small number of instances where the capture
> happened to minimize metameric problems, but can fail when subjected
> to comprehensive rigorous double-blind psychophysical testing when
> only the natural subject matter is included.
Actually, the differences I saw were relatively large.
I would agree that you can certainly apply more sophisticated testing,
because of all the reasons you pointed out. OTOH, from what I've seen
I think using camera target shots for evaluation is at least
meaningful in the sense that it evaluates *necessary* profile behavior
for camera accuracy. I.e. while such a test cannot guarantee that a
profile that showed only little color deviation in the test will never
fail under more complicated lighting conditions, it can at least say
that profiles that already show large color deviations under the
testing conditions are no reasonable candidates for profiles to
deliver color accuracy.
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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