Re: Large Format Inkjet & FOGRA Digital ISO Target
Re: Large Format Inkjet & FOGRA Digital ISO Target
- Subject: Re: Large Format Inkjet & FOGRA Digital ISO Target
- From: Mike Strickler <email@hidden>
- Date: Wed, 19 Aug 2009 22:46:26 -0700
Hi Christian,
The restriction of color gamut to match a press is accomplished by
conversion using the press profile before final conversion to your
inkjet printer's color space. In your RIP that will be either your
"source" (or "reference") profile or a "simulation" profile. This can
also be done earlier, at the application level. The exact arrangement
depends on your workflow and software. I can't comment more without
having the specifics of your situation. You may contact me off-list
for this.
Best regards,
Mike
MSP Graphic Services
423 Aaron St. Suite E
Cotati, CA 94931
707.664.1628
www.mspgraphics.com
On Aug 19, 2009, at 2:42 PM, Christian Macey wrote:
Hi Mike, thanks for clarifying a lot of 'output standard' issues
for me, it's really appreciated. I now understand a lot more than I
did a month ago with regard to hitting targets and proofing in
general.
Would it be annoying to ask one more question though? I'm lucky
enough to utilise a closed-loop colour management workflow at my
company. (Even with our new Vutek UV curable printer being
delivered next week.) But what I'm really concerned about is still
our workhorse HP Inkjets and the ONYX Production House RIPs
proofing capabilities.
With this in mind, can I ask how you personally go about reducing
the gamut of a profile for proofing purposes?
Christian Macey
On 3 Aug 2009, at 03:42, MSP Graphics wrote:
Hi Christian,
Well, the fact is that there are no real standards for inkjet.
There is simply too much variety in gray balance, gamut, etc.
among the models. AND, there is no real motivation to promulgate
such a standard, as manufacturers want the flexibility to produce
more and more color without limitation. Press is a different
matter. All 4-color litho presses use the same technology and inks
and can produce the same result, more or less. Furthermore, unlike
inkjets they are rather hard and expensive to profile individually
and so it makes even more sense to make them all match a standard
profile.
However, inkjets CAN be made to match each other, for example,
within the same company. It all depends what you want to achieve.
If you are doing inkjet production printing it makes sense to be
able to send jobs to any printer with the same result. In this
case you'd profile the printer with the largest color gamut and
use that as a source profile through which you'd convert files
going to the other printers, each of which of course would have
its own output/paper profile. Matching all printers to a common
RGB working space like Adobe RGB makes little sense for reasons I
won't go into here. Proofing is again another story. Here you
match all printers to a common reference press press profile. This
is the real intention of the Fogra wedge: It is a quick check for
compliance with press output values. It is not intended for
initial setup or evaluation of a system. For that you need a full
profiling chart of 1000+ patches such as an IT8.7/4.
Where are you located? What sort of operation do you have?
Depending on specifics we can give real-time tech support on these
issues on a one-time or contract basis. We also do sell all of the
tools required to maintain active color management in house. Let
me know if there is something we can do to help.
Best regards,
Mike
Mike Strickler
MSP Graphic Services
423 Aaron St. Suite E
Cotati, CA 94931
ph. 707.664.1628
fx. 707.939.4542
www.mspgraphics.com
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On Aug 2, 2009, at 2:25 PM, Christian Macey wrote:
Hi Mike, firstly thanks for taking the time to write a detailed
reply. With regard to simulating a Litho press from Photoshop
I've done this in the past with help from Chris Murphy's Real
World Color Management book. However, as you are aware I'd like
now to hit a 'standard' for large format Inkjet if possible. All
the machines I'm using on a daily basis are calibrated,
linearised and profiled correctly and very well in my humble
opinion.
After your great reply though as well as others on the ColorSync
list, I now think that I'm chasing rainbows for known inkjet
standards and will be better advised just to use Adobe 1998 RGB
to cater for this. What I'm getting at is I thought that FOGRA
had a new digital target for Inkjets only, and one could try to
get all machines inline by reading their output swatches.
I also thought that if other users (at different companies), of
the HP large format Inkjets I use were also measuring to known
values from this FOGRA digital target then we'd be on the same
page with respect to hardcopy proofs?
I hope you can find the time to reply once more.
Thanks again,
Christian Macey
On 15 Jul 2009, at 06:43, Mike Strickler wrote:
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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