Re: Colorsync-users Digest, Vol 6, Issue 154
Re: Colorsync-users Digest, Vol 6, Issue 154
- Subject: Re: Colorsync-users Digest, Vol 6, Issue 154
- From: Mike Strickler <email@hidden>
- Date: Tue, 14 Jul 2009 22:43:17 -0700
Hi Christian,
This can be implemented in a number of ways, depending on the RIP or
application. If the RIP has the option for a simulation profile that
would be the place to enter the first printer/paper profile, and the
file's original color space, e.g., Adobe RGB, would be the reference/
source. If there is no simulation option, first convert the file to
the first printer's output space and use that profile as the source/
reference. If you're printing from an application it depends: In some
you can use both source and simulation ("proof") profiles and in
others not, but the logic is the same. You mention targeting
different printers to the same external standard, e.g., a Fogra color
space, if I understand you correctly. Yes, you can do this, but this
makes sense only if you're press proofing. Remember, using a press
profile as a reference will reduce your output gamut to that of a 4-
color press, something you wouldn't want to do if you're printing
colorful RGB images on an inkjet for the final product. Simply using
a Fogra chart to make an inkjet output profile is another matter. I'm
assuming you've already profiled these inkjets. If not, then it would
be a good idea, especially if your paper and linearization/ink limits
deviate from those given in the RIP's preset print environments.
Rendering intents: First, conversions from RGB working spaces would
normally be perceptual or relative (w/Black Point Compensation) to
normalize the white point and preserve the general color balance when
shrinking the gamut to fit the printer's output space. When
simulating another printed output (press, inkjet, etc.) on an inkjet
printer the simplest scenario is the use of the same paper, in which
you should use rel. col, no BPC. In theory, absolute will give
identical results, but slight inaccuracies in the conversion will
result in dot being added to the background. In any area except press
proofing this is generally a no-no, so when the paper colors are even
close go ahead and use rel. col. Perceptual may not be as good a
choice for this conversion as this is not as standardized as rel.
col. and can result in "pleasing" mismatches. If the papers have
markedly different color and you absolutely must match the appearance
of the paper background the only viable choice is absolute
colorimetric. Just be sure to trim off the white border before
showing the prints to anyone.
These matters can seem quite difficult if you're new to color
management, so if in doubt I suggest contacting any of the many
capable individuals you contribute to this list to get a bit more
guidance.
Good luck,
Mike Strickler
Certified Implementer, EFI Proofing Products
www.mspgraphics.com
------------------------------
Message: 2
Date: Thu, 9 Jul 2009 21:02:01 +0100
From: Christian Macey <email@hidden>
Subject: Large Format Inkjet & FOGRA Digital ISO Target
To: email@hidden
Message-ID:
<email@hidden>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
Hi, hopefully there's some list members here that can help me please.
For the last couple of years I've been calibrating-linearising-
profiling the HP Z6100s and HP 5500s large format Inkjets using ONYX
Production House 7.x. Whilst there's been hiccups I think they're
printing rather nicely either through the RIP or directly from
Adobe's Suite and QuarkXPress 8 (thanks to the much improved colour
management preferences in QXP).
Primarily what I'm missing though and never totally understood is how
to match colour proofing targets. Especially when trying to get one
Inkjet to be a good match and close enough to another. Ideally, what
I especially need to accomplish is neutrality from profiled paper
stock to another as best as possible by editing the custom ICC
profiles for the machines, is this a good way to implement allowances
with an Eye-One Pro Spectro and ProfileMaker software. Or is
targeting the machines to FOGRA's new digital Inkjet ISO target v3.0
the best workflow, can you guys help me put the best foot forward
please as this is where I'm falling flat on my face with lack of
knowledge?
When trying to accomplish linearised/neutral media from different
machines I do think I have a chance here to make this work as I'm
only using one RIP (ONYX) for all the machines which I believe is a
very good idea and better provides for a closed loop when proofing
this way too.
One more point, is it recommended to use the Absolute Colorimetric
Rendering intent for matching different paper whites or should I just
match to the above target as the substrates won't differ to much,
maybe just different paper mill batch numbers?
It will mean a lot coming from this list for any pointers on any of
the above.
Many thanks,
Christian Macey
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