Re: Fingerprinting v Profiling (was Profile to standards or press?)
Re: Fingerprinting v Profiling (was Profile to standards or press?)
- Subject: Re: Fingerprinting v Profiling (was Profile to standards or press?)
- From: Busher Jr Richard C <email@hidden>
- Date: Tue, 1 Jun 2004 17:08:25 -0700
Hi All,
In my world (providing separations for a variety of clients, mostly for
sheetfed printing) I can only hope to profile the proofing systems of
the different printers I work with. I feel that trying to profile their
presses would be an exercise in futility.
Most of these shops have several presses, but usually only one proofing
system. They try to run the proofing system to achieve consistent,
repeatable results. I insist on color bars on the proofs so that I can
measure solid cmyk densities, plus dot gain in order to insure
repeatability. We agree on standards, i.e. + or - tolerance levels, and
if they are out of tolerance they remake the proofs, on their dime.
When I am happy with the results of the proofs my job is done, except
for the press check.
Their job is to 'finger print' their presses. My understanding is that
a finger print is essentially a curve correction applied to my file
before it is sent to the plate setter. The purpose of the finger print
is to have the press sheet match the proof when the ink densities are
dialed in on press. The finger print is created by first setting up the
press to run cleanly at the densities desired and on the stock/ink
combination be finger printed. Under those printing conditions plates
are made using plating curves (the finger prints) developed via trial
and error testing plus densitometry.
In my experience with CTP when printing on stocks that are similar to
the proofing stocks, ~ 75% of the time when they hit the target press
densities the match between press sheet and proof is excellent and
press checks are a matter of minutes. Approximately 25% of the time the
inks need adjustment, and occasionally a new plate may be required.
However, more often than not we simply print to the numbers. I've been
fortunate to have worked with excellent printers.
I usually send the printer untagged files. I do not expect any color
management by the printer in this work flow, unless you want to call
applying the finger print/plating curve a form of color management.
I do use color management in my shop. I create a profile for printer
XYZ. I then proof that file on my epson via a cmyk rip (Colorburst),
using the printer XYZ profile and my input profile, and an epson cmyk
(paper) profile as my destination profile. The correspondence between
my proofs and the proofs supplied by my printers is excellent (but
never perfect...nothing in this game is ever perfect).
I also use color management when working with supplied cmyk files.
Sometimes they are tagged. Sometimes they are not, and then I make an
educated guess. I always prefer to start with tagged rgb if I don't do
the scans, and I prefer to process camera raw files myself unless the
photographer understands printing.
When I produce separations for ads running in magazines I do tag the
files with my profile, and cross my fingers. My profile is my version
of swop dot gain plus the Kodak Approval color gamut, plus a TAC based
on what the printer tells me is appropriate for the paper and press
used, plus a gcr based on the image content. If the ad will run in
several magazines on different presses I would hope the color
management is used correctly. From what I've seen of the results it
seems to work for me!
Cheers,
Dick Busher
Cosgrove Editions
888/507-7375
email@hidden
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