Re: defining media white
Re: defining media white
- Subject: Re: defining media white
- From: "Bruce J. Lindbloom" <email@hidden>
- Date: Tue, 02 Oct 2001 12:00:26 -0500
Greg Staler wrote:
>
First - what type of measurement is generally used to describe whiteness of
>
the paper media. (For example - is it density, or XYZ, or something else
>
entirely?)
I think the value provided by the manufacturer represents reflectance. This
would correspond with the "Y" component of an XYZ measurement.
Greg again:
>
Second - what type of measurement would be suitable to describe whiteness
>
of plastic media (being used for printing instead of paper).
Reflectance, density, L* would all be appropriate as long as you were
consistent and were certain to communicate what your number represented.
I'm not sure if you are only concerned with "brightness" or if the color of
the material is also important.
As far as plastic media goes, I would advise that you discuss your project
with instrument manufacturers. Some substrates may have unusual surface
characteristics or translucency that may prevent them from being properly
measured with some instruments.
Tony Sanna wrote:
>
I figured that the LAB L-channel would confirm the mill's luminance numbers.
>
It didn't. The L-value from the SwatchBook was about 10% higher than the
>
specs. I don't recall the figures now, but the board's brightness was in
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the mid-80's, and my readings were in the low-90's.
This again indicates reflectance. A reflectance value of say 85
("mid-80's") would have an L* value of about 94 ("low-90's"), which agrees
with your measurements.
--
Bruce J. Lindbloom, Pictographics Intl. Corp.