Re: Optical Brighters while using UV Filter
Re: Optical Brighters while using UV Filter
- Subject: Re: Optical Brighters while using UV Filter
- From: Roger Breton <email@hidden>
- Date: Sun, 18 Jul 2004 15:19:55 -0400
>
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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