Re: Linearizing a press (was Re: Max K generation question)
Re: Linearizing a press (was Re: Max K generation question)
- Subject: Re: Linearizing a press (was Re: Max K generation question)
- From: Roger Breton <email@hidden>
- Date: Mon, 27 Sep 2004 21:27:05 -0400
>
I didn't mean to insult you Roger!
I was at light years away believing you would have.
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You'd be surprised; I've had OWNERS
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of printing companies question me, when discussing dot gain
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targets/linearization, as to "why shouldn't the press/paper measure 50%
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at the 50%?". I don't assume anything anymore!
Well that echoes my experience, here.
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When I'm "optimzing" a press for a specific dot gain target (i.e.
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GRACoL), I plot out a complete "desired" tone curve against the
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"actual" press behavior and make adjustments to the plate curves
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accordingly. I've got my own method for doing this but you'll be
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hard-pressed to find any info from folks like GATF or perhaps CGATS as
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to what the ENTIRE tone curve should look like. All they ever refer to
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is the 50%. In fact, as you start modeling a press's behavior, you'll
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very often find that the actual dot gain peaks at closer to 35-45%, not
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the 50%.
Terry, from the above, I see that I still have my homework to do. But it's
reassuring to see that there is merit in this idea of adequately modeling
the press behavior.
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I can tell you first hand, you get the whole tone curve right (by
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altering the plate curves) and you'll be able to make a "textbook"
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press profile that us old drum scanner guys like to see. Ask me and
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I'll send you a GRACoL DTR004 "ideal" (not!) profile vs. one I made
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from a Komori 6c press a few months ago and I'll show you what a GOOD
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press profile should look like!
Ahhhh! Being a long time PrintOpen user, I've always been baffled by the
shape of the dot gain curves at the end of measuring a press target. It's
plain to see that BestColor curves on an inkjet produces almost mathematical
tone value increase. But the same can't be said for all the printing presses
I've encountered (Close Encounters of the third kind?). I should send you
some screen grabs of some really weird presses I've profiled. It just broke
my heart having to create profiles under these conditions but there was
nothing I could do.
>
Roger, you coming to Graph Expo in Chicago? If so, let me know and
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we'll have to hook up.
I'd give my left testicule to make it. But it invariably falls right into my
teaching fall semester. I've already stretched as far as I could with the
dean of my faculty by missing one class at the end of october to attend some
color conference at the NY Fashion Institute of Technology. So, I won't be
able to go this time (again). Not that I wouldn't go. On the contrary.
Maybe we can link up somewhere else!
Regards,
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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