RE: The MESS at the PRESS campaign
RE: The MESS at the PRESS campaign
- Subject: RE: The MESS at the PRESS campaign
- From: bruce fraser <email@hidden>
- Date: Mon, 5 Apr 2004 14:38:07 -0700
At 10:36 PM +0200 4/5/04, Henrik Holmegaard wrote:
So what does it mean in practice if no conversion is used for the
print and a device link conversion (whether ICC or proprietary) is
used for the proof?
It means that there is no relationship between the print and the
proof. The print contains any mix of CMYK values while the proof
carries out a blind conversion which assigns the intended printing
condition as source and converts into the proof space.
The relationship between the print and the proof is that the proof
will show you what the document will look like on the printing
condition which the Dlink uses as source. If the document contains
totally incorrect separations, the proof will reflect that fact.
That's all I ask of a proofing system, that it follows the inexorable
law of Garbage In, Garbage Out.
The ECI white paper began with a piece of research that among other
things looked at the practices of ECI members with regard to non-ICC
visual adjustments as compared to ICC colorimetric adjustments.
Similar studies were carried out by many, IFRA and FOGRA.
Assuming the image designer and page designer are technically
literate, the studies suggest that with colorimetric adjustments
samples of proofs from many sites look more consistent than samples
of proofs based on visual adjustments.
Which is why the European Color Initiative works to promote open
standards ICC color management, ISO 12647 printing conditions which
are colorimetrically defined and self-certifiable, and PDF/X-3 which
makes PDF fully device independent.
In practice, I think it's time to retire the term
'device-independent' in all cases where it's applied to something
other than synthetic CIE color spaces. PDF is device-neutral, until
you actually display or print it. As soon as you do you so, it's
device-dependent.
This is a gradual process. Adobe Photoshop is now fully ICC-enabled
and the image design community accepts this as a significant benefit
over the simple forward rendering Adobe Sepation Table (AST) format
which no other application software supported.
As a point of order, AST's were bidirectional in Photoshop 3,
possibly in Photoshop 2.5 when they were first introduced, and a raft
of third-party applications supported them. That said, I'll be glad
when they disappear completely in Creative Suite 14.
Adobe InDesign 3 is the first page design application to support
fully invertible color mangement and text management in a situation
where proprietary proofing systems go hand in hand with ignorance of
the consistency benefits of device independence.
Adobe InDesign is an excellent application, but there is no such
thing as fully-invertible color management. Once you compress color
to a specific gamut, whether based on a device or on a synthetic
working space, you have performed a non-invertible operation-it's
strictly a one-way trip. We can play with perceptual renderings that
attempt to expand the gamut rather than compress it, but I've yet to
see one that will return the data I started with, though I've seen a
few that return a pretty picture.
It is possible that those clammering for advanced editing in ICC
device links will be given what they are clammering for, but ICC
device links will reseparate correctly if and only if ICC device
profile conversions have been used correctly at the prior stage,
either in image capture, image design or page design application
software.
Isn't that just a somewhat long-winded way of saying that color
management only works when you choose the right profiles and
rendering intents?
There are some here on this List who think that discussions of Adobe
InDesign don't belong. There are others here on this List who think
that standards-based printing and proofing don't belong. There are
even some who think that interoperability does not belong. Are you
folks sure you are talking about the real world -:).
We can discuss these things as much as you like. It doesn't change
the fact that if you send SWOP TR001 data today to 10 different shops
(ignoring the question of which SWOP TR001 profile you decide to use)
you'll get 10 different results. And I doubt that it will make many
users eschew non-interoperable technologies that provide predictable
good results in favor of interoperable ones that produce
unpredictable and sometimes bad ones.
--
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