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: Christian Macey <email@hidden>
- Date: Wed, 19 Aug 2009 22:42:01 +0100
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
<EFI Cert. Installer_G7.jpg>
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
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Colorsync-users mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden