Re: Inkjet Proofer Separation Parameters
Re: Inkjet Proofer Separation Parameters
- Subject: Re: Inkjet Proofer Separation Parameters
- From: Jack Kelly Clark <email@hidden>
- Date: Wed, 29 May 2002 08:12:11 -0700
In a message dated 5/28/02 1:34:58 PM, email@hidden writes:
I am profiling a commercial printer's HP5000PS inkjet proofer, which
they have carefully calibrated to their presses. I'm using
ProfileMaker 3.1.5. When setting the Separation Parameters for the
profile, should I use the numbers I got from the prepress manager
(UCR,Total Ink 310%, Maximum Black 98%, and Black Start ?) or
should I use one of the canned Inkjet Separation Parameter sets in
ProfileMaker?
You need to distinguish between the ink settings and black generation for the
press, and those for the inkjet. There is no direct relation between them,
except that one will related to the other when proofing the press on the
inkjet. Choose inkjet-based settings that work well on that particular
inkjet, with those inks, on that media. Be sure that all the color
adjustments in the internal RIP are shut off before printing the target...
this usually takes me about three tries for the 5000.
This printer is using a Heidelberg CTP system which included the
HP5000PS as a proofing device. The exact Heidelberg package I can get
later this morning. I think they told me they use PrintOpen to keep
the inkjet calibrated to the press. (Most likely I should provide
them CMYK files that are "untagged.") I'm assuming that the inkjet is
"tight" with the press, and maintained consistently in that state.
The numbers stated above are for the press. Based on some recent
experience with completely different shop that uses an Imation CTP
and a HP5000PS, I tried the following:
From the same test chart readings profiles were generated with three
different sets of separation parameters (one set based on their
press, and the two canned sets designed for "stand alone" inkjets
provided in ProfileMaker). Test prints from these three profiles were
all quite acceptable. All three were almost identical in color, but
the blacks were different. Because of the expense, the shop would not
make plates from these files and run them on the press to really
ascertain their quality. So, my main concern is, which separation
settings will produce the best plates? In the case of the shop with
the Imation system, the press separation parameters profile produced
an inkjet proof that had weaker blacks than the proof produced with
the profile that incorporated the canned inkjet settings. The
prepress manager there suggested I use the profile with the weaker
blacks to give the pressman some wiggle room. (This would be fine
assuming one can always be there for a press check.) The profile with
the canned inkjet separation parameters looked richer overall, and
one would want that "look" in the final printed piece, but the fear
of producing unmanageable plates has driven me to ask these questions
on the list.
--
Jack Kelly Clark
Principal Photographer
ANR Communication Services
University of California
Davis, CA 95616
(530) 757-8987
http://anrcatalog.ucdavis.edu
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