Jo,
we have already started the discussion to setup a working group web
offset within the ECI community. When Olaf Druemmer told me about
your conversation in Amsterdam we asked some web offset specialists
if and how a web offset production differs from sheetfed offset (in
terms of decsribing the process by a set of colorimetric reference
measurement data and sample profiles). It seems that there are
notable differences. Are there other web offset specialists out on
this mailing list with an opinion? The key issue: Does the web offset
community like to get dedicated reference printing conditions (e.g.
PSR for gravure and PSO for sheetfed offset) prepared and published
by ECI?
Mohn Media (a 'senior' member of the ECI community) would be willing
to kick-off such an effort, if the European web offset market wants
us to do so.
Kind regards
Stefan Brües
ECI chairman
Hello Jouni Marttila,
Good to get a specialist from the paper industry on board of this
discussion group!
I am responsible for colormanagement issues for our three weboffset
plants in the Netherlands which explains my interest in this subject.
We have done a great deal of testing and comparing proofing results
with standard profiles like the ECI "ISO Web coated sb" and our own
"custom profiles" with final press results.
We have mixed feelings about the practical use of the ECI web offset profiles.
First of al I must say that l there is a real need for standard ICC
profiles for web offset in Europe and we very much support the ECI
initiative as such.
As for the present ECI profiles however we have experienced that
using these for digital colour proofing in order to predict the
press results on our presses these profiles do not really do a good
job, at least not in our plants.
Possibly this has to do with the fact that the ECI profiles for
weboffset were made from prints that were actually produced on a
sheet-fed press.
From what I understand it has been tried to
simulate the print
characteristic of a web press in sheetfed offset.
(I guess this must have been a
hell of a job).
In my opinion however this is a very theoretical approach and I am
not surprised to see problems arise. Just think of different
trapping behaviour in weboffset versus sheetfed offset.
In our practice untill now we get a much better prediction of the
press results in digital proofing by using our own "custom profiles".
The problems we experience with the ECI profiles for web offset are
not in the area of maximum ink coverage, which is well defined in
these profiles.
The problems are in the colourspace of the profiles which is larger
than we see in day-to-day weboffset productions.
In web offset production we cannot achieve the high saturation
especially in the reds and violets which the ECI profiles for
weboffset predict in a digital proof.
The attached image shows the difference in colour space between the
ECI, the US SWOP and our custom profile.
Interesting enough our own custom profile is much closer to the U.S.
Web Coated (SWOP) v2 profile than to the ECI SO Web Coated sb
profile.
To our opinion it would be an interesting exercise to print
profiling test targets on a number of recently installed modern
weboffset presses in Europe to see what "real life" results are in
day to day practice and compare these results with the ECI profiles
for web offset which have been created on a theoretical basis.
I would be in favour of a new set of ECI weboffset profiles that are
more in line with day-to-day practical results and we would be
willing to cooperate in such an exercise.
Best regards,
Jo Brunenberg
Senior technology consultant Prepress / ICT
LOGIC USE BV
(member of Roto Smeets)
www.rotosmeets.com
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--
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Prof. Dr. Stefan Brües
University of Wuppertal
Fachbereich E - Advanced Communication Systems Laboratory
Rainer-Gruenter-Strasse 21
42119 Wuppertal, Germany
Phone: +49/202/4391167
Secretary: +49/202/4391300
Fax: +49/202/4391144
email: brues(a)uni-wuppertal.de
Website:
http://www.dmt.uni-wuppertal.de