Re: V2 vs. V4 profiles
Re: V2 vs. V4 profiles
- Subject: Re: V2 vs. V4 profiles
- From: Graeme Gill <email@hidden>
- Date: Wed, 17 Oct 2007 13:55:08 +1000
email@hidden wrote:
Has anyone personally had any experience with the 2 versions? The PDF says
that the V4 spec was designed to remove ambiguity and "Therefore, when
pairs of profiles are used they should always produce the same result –
regardless of which CMM is used.
A noble goal, but unfortunately it has worked in reverse in some
areas. For instance the ICCV4 vs ICCV2 L*a*b* PCS encoding (what a mess!),
and the display white point changes (ie. Absolute colorimetric now being
disabled for display profiles).
I'd actually recommend a more conservative approach - use ICCV2 unless
you know ICCV4 is going to solve a particular problem, or provide a feature
you need. You will get maximum compatibility that way.
[For instance, it's been pointed out to me that if you happen to have the
misfortune to run the Pantone Huey calibration package on your MSWindows system,
then (even if you abort out of it before completing a display calibration),
it instals a default Huey ICCV4 profile in your MSWindows profile
directory, and this profile causes Adobe Photoshop 5.5 to crash
on startup, because it chokes on one of the new tags as it scans though all
the profiles.]
Has anyone had any problems like this with V2 profiles? Has anyone had any
problems (like mine) where a particular program wouldn't work with a V4
profile?
Lots of programs will be compatible with V2 profiles, and will either
no (yet) support V4, or may have trouble with them, since they
are more complex (particularly while maintaining backwards compatibility
with V2 profiles), and it's all less well tested due to the classic
chicken and egg problem. There were some problems recently noticed
caused by the V4 multilingual comment tags for instance, triggering
latent bugs in various applications.
The more flexible V4 LUT's could pose a problem in particular for
profile editing tools, since the tools whole approach may have to be
re-worked to cope with the extra flexibility.
Graeme Gill.
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