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: Todd Shirley <email@hidden>
- Date: Tue, 29 May 2007 13:40:31 -0400
Matt
Welcome to the great UV debate! You'll will probably get some very
adamant postings both for and against using UV light in your
spectrophotometer, and most likely none of them (including this one)
will help clear up your confusion. There are several factors which
make this subject so contentious, but I feel that it mainly comes
down to total lack of standardization - There is no standard
measurement for how much optical brightener is used in paper stocks
(and thus no classifications based on OBs), or how different OBs
fluoresce in different ways. There is no standard for how much UV
should be present in a given lighting condition, although there
certainly will be SOME UV. Finally, there is no standard for how much
UV is present in the lamps of different measurement devices, and no
consistent way in which the fluorescence is measured.
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!
I personally use Monaco Profiler to make profiles, which does not
"compensate" for optical brighteners like ProfileMaker does, but I
don't really understand what "software correction" means. Can anybody
fill me in on what exactly Profiiemaker is doing that Monaco Profiler
isn't? Beyond this confusion, I have read on multiple forums,
including this one, that the compensation that ProfileMaker does only
applies to the perceptual rendering intent, which I rarely if ever
use, especially at the RIP. Does anyone know if this is true?
So now I lean towards filtering out UV, mainly because OBs are such a
wildcard that including them just adds another uncontrollable
variable to a process that already has plenty. Perhaps the paperwhite
values and highlights will suffer a little, but at least my profiles
and proofs will be consistent across multiple measurement devices.
I'm sure others have differing opinions, and we'd all love to hear them!
-Todd Shirley
Urban Studio
New York
Matthew Larmour wrote:
I am trying to weigh the pros and cons between getting a UV filtered
spectro (probably an EyeOne) and a non UV filtered spectro.
I will be profiling a variety of papers, some with optical
brighteners, some without, printed mostly on digital presses. The
lighting under which the final prints will be viewed will vary:
incandescent, fluorescent, natural light.
I'm wondering if the safest way to go is to go UV filtered. I'm
considering going with ProfileMaker, which apparently has software
correction for OBs, but I'm not sure if it can be relied on.
Any recommendations or thoughts to clear up my confusion on the way
to go with this would be most appreciated.
Thanks,
Matt Larmour
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