Re: Measuring Optical Brightners
Re: Measuring Optical Brightners
- Subject: Re: Measuring Optical Brightners
- From: Nicholas Androulidakis <email@hidden>
- Date: Fri, 27 May 2005 14:44:00 -0400
Is there a list available somewhere of papers that do or don't use optical brighteners?
For example a listing that might say whether Epson's Professional Semimatte or Enhanced Matte or Han. Photo Rag use optical brighteners?
Nick
Nicholas Androulidakis
email@hidden
On May 27, 2005, at 2:34 PM, Steve Upton wrote:
At 11:05 AM -0700 5/27/05, Steve Lehning wrote:
I was curious what I could use to measure Optical
Brightner in Proofing and Printing stock. We have an
eye-one Spectrophotometer and the eye-one software. We
also have Profile Maker 4.0. We were searching in
these applications for something that would be
applicable. However, we could not find what we should
be using, and if we did what are some of the readings
that show a tolerance factor for these measurements.
In other words at what value is a stock considered as
having noticeable optical brightners.
GretagMacbeth has programmed the ability to detect it into their ProfileMaker and (invisibly) the Eye-One Match software. I don't think there is a simple utility to show the presence of whiteners except to load a spectral data file into ProfileMaker as if you were going to build a profile. If (PM thinks) there are brighteners then the "optical brighteners" checkbox will be enabled. It seems to catch most cases of it.
If you view spectral curves of paper white readings then it shows up as a tell-tale "hump" in the blue end of the spectrum and a corresponding drop in the nearby UV area. Compare it to a UV-filtered reading (if you can take one) or a well-behaved art paper like Arches and you will see the difference immediately
Regards,
Steve
________________________________________________________________________
o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX
o email@hidden 206.985.6837
o ColorGear ColorThink ColorValet ColorSmarts ProfileCentral
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