Dan Margulis Applied Color Theory
The TR001 Standard and Proofing
Date: Sat, 29 Mar 2003 21:37:22 -0800
From: Richard Chang
Subject: TR001 proofing
List:
I can believe that the press is capable of TR001 like
behavior, however I've never seen it on a real run, on a coated, heatset
web running a #4 commercial stock. I do know that the printer of
record is not holding 1% highlights and 98% shadows. Given this
printing condition, why is a TROO1 a reliable predictor of a traditional
press that does not mimic the TR001 digital proof's highlight and shadow?
If I shoot a digital file using the TR001's highlight and shadow, and
get the press' normal 3% highlight and 93% shadow, where do I send my
complaint that important highs blew out and important shadows plugged?
Profiling presses is somthing that GATF has suggested
is possible, but I have yet to believe it is common practice in the
"real world". Could I be so cavalier as to ask the printers
on the list to chime in as to their use of profiling their output on their
presses?
Richard Chang
________________________________________________________________________
Date: Sun, 30 Mar 2003 04:21:11 -0700
From: Andrew Rodney
Subject: Re: TR001 proofing
on 3/29/03 10:37 PM, Richard Chang wrote:
I can believe that the press is capable of TR001 like
behavior, however
I've never seen it on a real run, on a coated, heatset
web running a #4
commercial stock.
From a post of Chris I archived, he indicates that ANSI
had a CGATS committee perform a SWOP certified press test conforming to
SWOP. On this press test they printed the IT8.7/3 press test target (a
standard target of 928 patches of different combinations of CMYK values)
and then measured the target and averaged it all out and then called it
TR001 and said "this is SWOP". So CGATS was apparently able to
produce this on press in a repeatable manner and measure/average this data.
Profiling presses is somthing that GATF has suggested
is possible, but I
have yet to believe it is common practice
in the "real world".
I1ve done it on a few presses (The newer Komori1s
specifically) that were very well controlled and at shops where process
control isn1t an afterthought. I am positive that others including Chris
has done this. It1s not an insurmountable obstacle assuming a well run and
maintained press that undergoes through process control.
Do a Google search for SWOP TR001 and you1ll find all
kinds of references to this.
Andrew Rodney
________________________________________________________________________
Date: Sun, 30 Mar 2003 08:31:38 -0500
From: Terry Wyse
Subject: Re: TR001 proofing
on 3/30/03 12:37 AM, Richard Chang wrote:
Profiling presses is somthing that GATF has suggested
is possible, but I
have yet to believe it is common practice in the
"real world". Could I be
so cavalier as to ask the printers on the list to chime
in as to their use
of profiling their output on their presses?
Speaking for somebody who does press profiling FOR
printers, presses DO get profiled in the "real world", or at
least in my world. Usually it's done in conjunction with the
"introduction" of a piece of color management workflow gear such
as on inkjet proofing system of some sort, otherwise there's not much
incentive to profile a press.
Regards,
Terry Wyse
__________________________________
WyseConsul
Color Management Consulting
v 704.843.0858
__________________________________
________________________________________________________________________
Date: Sun, 30 Mar 2003 10:53:01 -0800
From: Richard Chang
Subject: TR001 proofing
List:
Perhaps I should attempt to ask the printer of record
about profiling their presses. I do have a question however, which
involves my limited understanding of presses. Am I to assume that the
process control of a sheet fed Komori is the same as a heatset web?
Certainly the speed of the press is different, the paper stock is
different, and the inks are different. Doesn't the faster running
press using less viscous inks on more absorbent paper, vary more with
respect to unprofileable variables like humidity, blanket and plate
degradation? How about gravure presses, are these being profiled as
well?
Richard Chang
________________________________________________________________________
Date: Sun, 30 Mar 2003 22:03:24 EST
From: Dan Margulis
Subject: Re: TR001 proofing
Richard writes,
I can believe that the press is capable of TR001 like
behavior, however
I've never seen it on a real run, on a coated, heatset
web running a #4
commercial stock. I do know that the printer of record
is not holding 1%
highlights and 98% shadows. Given this printing
condition, why is a TROO1 a
reliable predictor of a traditional press that does not
mimic the TR001
digital proof's highlight and shadow?
The question is not whether it's particularly reliable
but rather whether it's better than whatever else you have in mind. If you
feel like editing the profile to cater to this known behavior, then you'll
have very, very marginally better results, but it hardly seems worth the
bother in view of the ease of setting slightly more conservative endpoints.
If I shoot a digital file using the TR001's highlight
and shadow, and get
the press' normal 3% highlight and 93% shadow, where do
I send my complaint
that important highs blew out and important shadows
plugged?
To the last known address of Richard Chang. Presses are
simply not reliable enough for us to place bets like this. Even if you are
going to a sheetfed press that has a history of holding 1% dots you have no
guarantee that it'll hold them on your job. If your highlight detail is so
critical that losing its lightest areas would be unacceptable, you
unfortunately have to assume that they *won't* hold 1% and go slightly
darker.
Am I to assume that the process control of a sheet fed
Komori is the same
as a heatset web? Certainly the speed of the
press is different, the paper
stock is different, and the inks are different.
Doesn't the faster running
press using less viscous inks on more absorbent paper,
vary more with respect
to unprofileable variables like humidity, blanket and
plate degradation?
Right on all counts. But what are you going to do about
it? You still need to assume *something* when you make your separation. You
just shouldn't take it too seriously. You'd think that the idea would be to
get as close as you can to what you think the most likely outcome is, but
that won't get the best results in the real world. Instead, you want to be
optimistic about the press's highlight and shadow capabilities, and
pessimistic about its dot gain. In other words, you assume the worst, and
hope for the best. Risking blown-out highlights is normally a better bet
than risking a flat picture. Too light is better than too dark in most
pictures.
How about gravure presses, are these being profiled as
well?
Not in the sense of somebody printing swatches and
measuring them. The reason gravure is pretty much reserved for runs in
excess of 100,000 is that the running cost of the press is quite low but
you have to get past a horrendously high makeready charge. Engraving copper
cylinders is really, really expensive, so test runs on gravure presses are
generally out of the question. They get profiled by eyeball, based on live
jobs.
Dan Margulis
________________________________________________________________________
Date: Mon, 31 Mar 2003 09:16:49 +0000
From: Martin Bailey
Subject: Re: TR001 proofing
At 11:21 30/03/2003, Andrew Rodney wrote
:
From a post of Chris I archived, he indicates that ANSI
had a CGATS
committee perform a SWOP certified press test
conforming to SWOP. On this
press test they printed the IT8.7/3 press test target
(a standard target
of 928 patches of different combinations of CMYK
values) and then
measured the target and averaged it all out and then
called it TR001 and
said "this is SWOP". So CGATS was apparently
able to produce this on
press in a repeatable manner and measure/average this
data.
Personally I'd argue that both sides of this are true.
The TR 001 measurements were, indeed, performed under
the supervision of CGATS SC3 to match the SWOP specification, and SWOP has
back-adopted the measurements as a colorimetric definition of SWOP
compatibility.
The SWOP spec itself (as opposed to TR 001) has some
reasonably large tolerances, which means that many presses can be coerced
into printing within spec. Take care, however, because quite a few of the
printers who claim to print according to SWOP don't actually get all that
close.
To my mind, however, I believe that the real value of
SWOP (as described in TR 001) is not as a spec to which a press should
necessarily be adjusted, but as a CMYK exchange color space. If all parties
involved in origination, prepress and the press room can agree to a common
standard in which data can be encoded then the amount of personal
interpretation involved in determining whether a print is 'correct' should
be reduced.
I don't think it matters if the press operator achieves
the correct color by adjusting the press, by channel-wise calibration in
the plate-maker to compensate for different dot gain, or by full-blown
color management. If the color is right then the color is right.
Yes, there are obvious caveats about maintaining pure
inks (especially black), and about keeping neutrals neutral, but many of
those need careful control whatever approach is used.
Regards
Martin Bailey
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+44 1223 873800
Global Graphics Software
http://www.globalgraphics.com
Harlequin - Jaws -
MaxWorkFlow
martin.bailey@globalgraphics.com
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If my views didn't usually coincide with those of my
employer
I wouldn't want to work here, but I am not a
spokesman for
Global Graphics Software
and the buck stops
with me for what I say.
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________________________________________________________________________
Date: Mon, 31 Mar 2003 10:15:10 -0800
From: Richard Chang
Subject: Re: Re: TR001 proofing
List:
Dan wrote:
The question is not whether it's particularly reliable
but rather whether
it's better than whatever else you have in mind. If you
feel like editing the
profile to cater to this known behavior, then you'll
have very, very
marginally better results, but it hardly seems worth
the bother in view of
the ease of setting slightly more conservative
endpoints.
The idea here is not to simply shoot more conservative
endpoints, I'm already doing that because I know the endpoints of the
press. I was wondering if we could adjust the TR001 so that it mimics
the press, thereby allowing it to be a real proof, one that allows viewing
the customers images as they will likely print. At the moment, the
TR001's behavior doesn't match the press.
Perhaps I don't understand editing the profile to cater
to known behavior, why wouldn't I want to do that?
My current procedure involves rendering a Target
Characterizer file, a gradient that allow seeing the highest and lowest
separable value on the target. Using this file, I can see the TR001
proof's endpoints and I know they're not typically held by most heatset web
presses. Of course I can (and will) hold the press' known endpoints
as separation parameters but the TR001 looks muddy in the highs and too
open in the shadows. If a proof doesn't match the behavior of the
target, can it still be called a proof?
It would seem that there may be two obvious avenues.
Change the TR001 so that it reflects a real world operating
environment, or, attempt to change the press to match the TR001's behavior.
Unfortunately, the latter choice forces a change that I don't know
the printer is interested in, nor has the printer expressed any interest in
a change.
Because the printer has been doing a fine job and no
one's unhappy, I'm more interested to find out if I can implement a change
(profile?) to the TR001 so that it accurately reflects the press. I
do realize that the proof would no longer be TR001 but that's not my
problem since I don't want a TR001 proof.
Perhaps I'm out of luck. It could be that the
TR001 won't allow my customer to predict the press' behavior, unless the
press can be made to mimic the TR001's behavior.
Richard Chang
________________________________________________________________________
Date: Mon, 31 Mar 2003 12:24:53 -0700
From: Andrew Rodney
Subject: Re: Re: TR001 proofing
on 3/31/03 11:15 AM, Richard Chang wrote:
Perhaps I don't understand editing the profile to cater
to known behavior,
why wouldn't I want to do that?
Editing the profile isn1t the answer (it1s not even the
issue or problem; I have no idea what Dan is referring to). Trying to edit
a profile to match the press or other output simply because the profile
doesn1t accurately fingerprint the device (because likely a custom
fingerprint/profile wasn1t made in the first place) is as silly as
adjusting your display to match someone1s print.
The idea is the profile accurately fingerprints the
press (or more often in this country, the contract proof). If the press or
proof can1t be managed to be consistent, the fix isn1t editing a profile.
The fix is called process control. Profiles or not, without process
control, the entire workflow is in chaos.
The 3beauty2 of TR001 is that it1s a reproducible
behavior that has been spec1ed and agreeable by at least a large number of
users and organizations including CGATS. It1s certainly not a 3standard2
but it1s an aim point. I question why more printers don1t try and at least
nail their output conditions on something that can be measured and others
can shoot for. I don1t see any benefit in making devices that should behave
in a consistent fashion not do this. I suspect that some printers would ask
themselves why they would want their press to behave like the guy1s down
the street. But for the end user or someone hoping to optimize their
conversions for output, it1s really a pretty sweet position to be in.
My current proceedure involves rendering a Target
Characterizer file, a
gradient that allow seeing the highest and lowest
separable value on the
target. Using this file, I can see the TR001
proof's endpoints and I know
they're not typically held by most heatset web presses.
But can they be?
It would seem that there may be two obvious avenues.
Change the TR001 so
that it reflects a real world operating environment,
or, attempt to change
the press to match the TR001's behavior.
The latter! The former only guarantees what we
already have which is presses that don1t conform to anything other than
what the people running the press want or think the behavior should be.
That may make them happy but doesn1t help us end users.
Unfortunately, the latter choice
forces a change that I don't know the printer is
intersted in, nor has the
printer experssed any interset in a change.
Fortunately there are plenty of printers and those that
make our life's easier will hopefully be rewarded with more business.
Knowing that your background is Photography Richard,
let me ask you what you1d prefer in a different kind of process, E6. Would
you be willing to work with lab1s who1s idea of normal processing, push
processing +1/3 and so forth were all over the map? Or would you be happier
knowing that if you sent the same exposed film to 10 labs where conformed
to what is a specification of E6, you1d get pretty much the same results?
We both know you need to test emulsions and labs to really nail identical
results from each. But I1d be hard pressed to believe that too many pro
labs would be off more than a quarter of a stop in either direction (within
tolerance of ending up with a usable piece of processed film). Imagine of
the fudge factor were over a stop, let alone 25cc1s of color! SWOP is (as
defined by all the printers who say they print to SWOP) far worse than
that! I have dozens upon dozens of spectral data files of the same kind of
contract proof (Matchprint) and the variations are alarming to say the
least. I do find some shops thousands of miles apart having average deltaE
readings in the 2-3s. Not bad. I can also illustrate deltaE1s of the same
contract proof in the 12 to 20 range. Totally unacceptable. How can we
measure with a rubber ruler? Yet each of these shops will tell you 3we
proof on Matchprint to SWOP2 and clearly many are all over the plant.
Editing a profile isn1t the answer. Process control and 3standards2 (which
TR001 attempts to provide) is the right way to be moving.
Andrew Rodney
________________________________________________________________________
Date: Mon, 31 Mar 2003 21:07:43 -0500
From: Bob Johnson
Subject: Re: Re: TR001 proofing
Not in the sense of somebody printing swatches and
measuring them. The reason
gravure is pretty much reserved for runs in excess of
100,000 is that the
running cost of the press is quite low but you have to
get past a
horrendously high makeready charge. Engraving copper
cylinders is really,
really expensive, so test runs on gravure presses are
generally out of the
question. They get profiled by eyeball, based on live
jobs.
Dan Margulis
Well, we're trying.
We're running swatches and measuring them, almost
daily.
It's a HUGE task with the variety of substrates, inks
and finishing
operations involved.
We've run several situations to ground and over the
past 6-9 months have had
several impressive successes, involving projects
running 250+ line screens
on "narrow web" gravure and more common (150
lpi) rulings on the big (60+")
iron.
We're also making a big effort for flexo. Variations,
within the same shop,
with mounting, press crews and during the run are
amazing. Things are so
far out of "normal" from one end of the run
to the other it's almost a waste
of time to generate the numbers.
________________________________________________________________________
Date: Mon, 31 Mar 2003 21:57:44 EST
From: Dan Margulis
Subject: Re: TR001 proofing
Richard writes,
I was wondering if we could adjust the TR001 so that it
mimics the press, thereby
allowing it to be a real proof, one that allows viewing
the customers images
as they will likely print. At the moment, the
TR001's behavior doesn't match
the press.
TR001 is a consensus spec. Most printers *don't* match
it, but some will match it closer than others. If you have no clue who is
going to print the job then a consensus spec is all you have and this is
likely to do as well as any other.
Even if you do know who the printer is, they may be
able to match the spec reasonably on one shift and not the next. This has
been a fact of life for as long as offset printing has existed.
Perhaps I don't understand editing the profile to cater
to known behavior,
why wouldn't I want to do that?
Because it's politically incorrect, and suggests that
you don't think a printing press and a photo lab are one and the same
thing.
Of course I can (and will) hold the press' known
endpoints as separation
parameters but the TR001 looks muddy in the highs and
too open in the
shadows. If a proof doesn't match the behavior of
the target, can it still
be called a proof?
It can, but perhaps not a very good proof. The
questions are always two: First, is there a consistent pattern you can
detect as to why the proof is defective? If not, it's just random variation
and there isn't much you can do about it. Second, is it worth the bother to
correct, granted that it has to be done outside of Photoshop?
In your case it looks like you have a yes answer to #1.
Whether #2 gets a yes or no is very much up to you.
It would seem that there may be two obvious avenues.
Change the TR001 so
that it reflects a real world operating environment,
or, attempt to change
the press to match the TR001's behavior.
Exactly right. Those are the two options. To me this is
the choice between flying out to see the Grand Canyon or insisting that the
Grand Canyon be brought to us; the choice between screwing in a light bulb
and insisting that somebody turn the ladder while we hold the light bulb in
position.
While I basically approve of the TR001 initiative,
you're running into one of its limitations. It's been propounded by people
who are concerned about quality and willing to spend time and money to get
it. These people are a lot more likely to have modern presses and CTP than
most. So, unfortunately, they've come up with a spec that's a reasonable
aim point, but which many printers nevertheless can't achieve. A lower
common denominator might have been in order.
You're seeing one of the major problems of color theory
vs. *applied* color theory here. In calibrationist heaven, clients are very
perturbed when the proof doesn't match the printed result, full stop.
On my planet, the clients are very perturbed when the
proof looks *better* than the printed result, not when it doesn't match. If
the two don't match but the printed result looks better than the proof,
there are very few complaints in my experience.
Dan Margulis
________________________________________________________________________
Date: Tue, 01 Apr 2003 06:47:28 -0700
From: Andrew Rodney
Subject: Re: TR001 proofing
on 3/31/03 7:57 PM, Dan Margulis wrote:
You're seeing one of the major problems of color theory
vs. *applied* color
theory here. In calibrationist heaven, clients are very
perturbed when the
proof doesn't match the printed result, full stop.
On my planet, the clients are very perturbed when the
proof looks *better*
than the printed result, not when it doesn't match. If
the two don't match
but the printed result looks better than the proof,
there are very few
complaints in my experience.
So the new 3color theory2 slogan based on this is 3If
it1s broke, don1t fix it2 or, don1t worry about turning the light bulb or
the ladder, just sit in the dark. A not moto for the 21st century? I
certainly hope not!
Those damn calibrationist have a lot of nerve wanting a
proof and press to match!
Andrew Rodney
________________________________________________________________________
Date: Tue, 1 Apr 2003 10:03:58 -0500
From: "Remaley, Dan"
Subject: Color matching and TR001
In the past, as attempt to measure the printing
process, we have used SID (Solid Ink Density), dot gain, gray balance,
print contrast, trap, etc. to 'measure' the quality and control of the
process. Yes, it is a process, and it is repeatable, but it has a lot of
variability. Measuring only one or two of the above items cannot control
the process, we must measure all of them! TR001 attempts to define a print
condition, it can be measured and repeated IF the press variables measured
are controlled. Think of printing as a process, in scanning we must know
the color of the inks, the press gain and most importantly, what colors
make gray at press. Without process control how can we answer these
questions? Since we don't know the answers to these questions, we scan to a
'standard' (SWOP), then it's up to the press to conform for SID, dot gain,
gray balance. Example- a scan made for SWOP with a 20-22% midtone gain
won't print well on a CTP linear plate system, where the gain is 15-17%.
Ditto for Pantone color builds designed with a 22% gain. The same applies
for gray balance. What if your using a Rhodamine magenta instead of Rubine
magenta, you are going to need more cyan to create gray. Let's suggest that
you have profiled a press and the cyan prints higher than magenta, in
density and gain (this is opposite of the standard). We can 'calibrate' for
this difference in scanning and proofing, but what caused this abnormal
condition? Aren't we "masking" the problem? What about our
scanning gray balance numbers? Where's our process control now? What
numbers?
I recommend controlling the press to a standard
before the printing of an IT.8 or color management target. Since January 1
have written several articles on process control for the Newspaper &
Technology magazine, their standard is SNAP.
GATF has introduced "System GATF" a guide on
the process and control of every step in the process, for a free poster,
please send me your complete mailing address.
Dan Remaley
Process Control Tech.
Graphic Arts Technical Foundation
412.741.6860x450
________________________________________________________________________
Date: Fri, 11 Apr 2003 19:39:05 -0600
From: Chris Murphy
Subject: Re: TR001 proofing
On Friday, March 28, 2003, at 08:33 AM, Richard
Chang wrote:
The TR001 easily holds 1% in the
highlight and 98% in the shadow, which are not values
which can be
replicated by the press, the printer of record has been
printing this job
for several years and we know the highlight is about 3%
and the shadow
about 93%. I can imagine the TROO1 standard to be
a linearization which
does not necessarily reflect a press' behavior.
TR001 was achieved on press so by definition it
reflects press behavior - under the conditions for the press run used.
Can the new proofing systems match the older
system's ability to allow us to see how important
transitions to hightlight
and shadow perform?
Yes. But this is independent of TR001. You can have
TR001 as a press behavior, or you can have something else, like a custom,
optimized behavior. Regardless, what you want is for the proofer to
simulate that behavior. That way it will predict what will happen when a
job ends up on press.
Is profile editing the direction I
should be thinking about, can I appropriately append
the endpoints
without re-inventing the wheel?
Ultimately some profiling editing may be necessary in a
couple of areas: first to ensure RGB images are being properly separated to
CMYK. Next editing profiles for both soft proofing and hard proofing which
means editing the CMYK to LAB portion of the press profile. Finally editing
the proofer profile as needed so that it matches optimized press behavior.
Ideally, the test images are printed on press (if you decide to actually
profile the press) at the same time as the profile test target. Once the
proofer simulates this actual press run the goal is to make the press match
the proof. By doing this, you will always be forced into bringing the press
back to the reference, optimized behavior and it will be relative easy to
do this because the proofing system is simulating something the press has
already done anyway.
The problem with analog proofs is that they represent
an ideal press behavior that isn't based on actual press behavior. So they
are inherently more difficult to match.
Chris Murphy
Color Remedies (TM)
www.colorremedies.com/realworldcolor
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