Re: UV filtered vs. non UV filtered spectros
Re: UV filtered vs. non UV filtered spectros
- Subject: Re: UV filtered vs. non UV filtered spectros
- From: Terry Wyse <email@hidden>
- Date: Tue, 29 May 2007 15:16:37 -0400
On May 29, 2007, at 1:40 PM, Todd Shirley wrote:
Welcome to the great UV debate!
Indeed!
For a long time I was of the school that UV should be included in
measurements and subsequent profiles, because UV will be present in
all viewing conditions. Now I'm not so sure. My troubles started
when I went from having one spectro (a Spectrolino) to 3:
Spectrolino, i1 ISIS, i1pro. All three devices can have UV
included, and all three return significantly different numbers on
paper white values of stocks with OBs. Each device has its own
"way" of measuring the effects of OBs, and thus some came up with
brighter and/or bluer numbers than others. On some stocks the dE
between devices of the paper white is over 2!
Just curious Todd, did you find that when measuring papers with UV
EXcluded that all of your spectros measured paper white more-or-less
the same/more consistently (< 1dE)?
I'm sure others have differing opinions, and we'd all love to hear
them!
"You asked for it, you got it (Toyota!)" :-)
I would say your final desicion depends more on where your data is
coming from as opposed to the relative merits of UV included or
excluded.
If you'll be using exclusively your own measurement data, then I
would say it doesn't matter all that much. Basically, if the same
instrument is used to measure and create both the source and
destination profiles, you'll be OK either way.
But if you start using "outside" characterization data or profiles,
then it could/will matter.
In the world in which I live (inkjet contract proofing systems) where
you might generate your own source data but where we are increasingly
relying on "standard" characterization data such as
GRACoL2006_Coated1 or perhpas FOGRA data sets, these are, by
definition, created/measured with UV-included. So if you were to use
one of these standard data sets/profiles but you created your
destination profile with a UV-cut spectro, your visual match would
not be correct. There are ways around this but unless you're using
something like a GMG RIP, which allows direct editing of measurement
data ("target values"), it can get pretty ugly trying to edit
profiles to compensate for this difference. The accepted standard for
pressroom measurements and characterization data is to use UV-
included measurements so that's basically what I've stuck to with
most of my spectros.
If it were me, I'd stick with a spectro that offers BOTH options
(DTP70, iSis, Spectrolino) or simply purchase two Eye-Ones so you're
covered either way.
Regards,
Terry
_____________________________
WyseConsul
Color Management Consulting
G7 Certified Expert
email@hidden
704.843.0858
http://www.wyseconsul.com
http://www.colormanagementgroup.com
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