RE: Optical Brighters while using UV Filter
RE: Optical Brighters while using UV Filter
- Subject: RE: Optical Brighters while using UV Filter
- From: "Cedric Briscoe" <email@hidden>
- Date: Sun, 18 Jul 2004 16:15:44 -0400
I don't buy the fitted/non-fitted, Neutral paper, same results either. But I
have been leaning in the direction of; if you find yourself having to
profile some strange printer on God only knows what stange stock (some
glossy stuff for the corporate environment) with [maybe] Brighteners galore,
you will STILL get to go home on time.
I've never tested myself; I just started and stayed with UV filters and
quietly said, "It's better to have it and not need it; then need it and not
have it."
Ok. My next instrument will be without the filter. BUT, the FIRST yellow
cast I see, I'm comin' ta get that HP Profile AND its accompanying roll of
Paper - so don't print TOO much <grin>
I wish I knew what position Monaco will take on this with their next version
of MonacoPROFILER (Which is my personal favorite for pre PM5; if ONLY for
the reason it will put a device linearization in the profile, applied to the
patches for the times you can not linearize (no rip, Color Laser, Color
Copy, etc.)
Don't tell me High End Scanners (Cruse) don't need polarizing filters. A
Hutch Color Target and all the gamma tweeking in the world couldn't prevent
the Specular White from ruining my other wise perfectly good scans.
I have to admit, I have NEVER had a difficult paper to profile. I have
profiled some no-so-great stocks but never anything that gave me a problem.
I use some 130gsm plain stock (no type of coating) for double-sided 8up
impositions and although the TIL is about 186 (which REALLY isn't bad for
what it is), the color was true with only a reduction in contrast - which is
to be expected. Maybe I've been lucky.
Cedric Briscoe
Treetop Publishing, Inc.
-----Original Message-----
From: email@hidden [
mailto:email@hidden]
Sent: Sunday, July 18, 2004 3:20 PM
To: Cedric Briscoe; email@hidden
Subject: Re: Optical Brighters while using UV Filter
>
I guess the [negative] impact is only on papers with a large amount of
>
Brightners.
>
>
Cedric Briscoe
I have not systematically tested that hypothesis. But I don't believe that's
what's going on? To me, no matter the level of OB, the UV fitted instrument
artificially distorts the measurement. And I don't buy the argument that
provided a perfectly neutral paper (no OB) that a fitted vs a non-fitted UV
instrument yield the exact same measurement?
Another area I'm having problem with is the source in these instrument. Yes,
the source is mostly tungsten -- Illuminant A. We all know that there isn't
much UV energy in Illuminant A sources to begin with. So I wonder to what
extent does a UV filter incorporated inside an instrument which does not
produces much UV energy to begin with is all that effective? For my money, I
tend to think that it's best to NOT filter the UV excitation OR use a Xenon
type of source spectrophotometer like a SpectroCam, which produces a whole
heack of a lot of UV energy and thus excites a lot of fluorescence out of
the OB in the paper. I created my best HP 20ps profiles with a SpectroCam, I
might add.
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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