Re: Measuring Optical Brightners
Re: Measuring Optical Brightners
- Subject: Re: Measuring Optical Brightners
- From: Steve Upton <email@hidden>
- Date: Fri, 27 May 2005 11:34:56 -0700
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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