RE: Re: What is the best Spectrophotometer for reading canvas (Steve Lawrence)
RE: Re: What is the best Spectrophotometer for reading canvas (Steve Lawrence)
- Subject: RE: Re: What is the best Spectrophotometer for reading canvas (Steve Lawrence)
- From: email@hidden
- Date: Tue, 1 Apr 2003 11:03:23 EST
Simply put, there are two commonly used geometrys for reflection color
measurement: 45/0 and D/0. ICC colorimetry is built around the former and the
latter (aka as integrating sphere) is frequently used in the textile
industry, among others. 45/0 is appropriate when the sample has a well
defined gloss component. The idea is that when viewing glossy (or semi-gloss)
samples, viewers position samples in such a way that the gloss does not
bounce into the viewers eyes. 45/0 geometry attempts to exclude this specular
component and instead measure the diffuse component which carries the color
information. Textile samples generally have a more irregular surface without
a well-defined specular component. To average out the irregularities, textile
samples are generally measured diffusely (from all directions). So for these
samples, sphere geometry may be more appropriate. 45/0 and sphere
measurements of the same samples generally give different measurements, and
ICC colorimetry is built around the former, so simply switching to sphere for
the textile samples may or may not be a fix. Most of the major color
instrument manufactures have sphere instruments. But since they are intended
mainly for industrial applications, you may be in for a bit of sticker-shock.
Eric Walowit
Tahoe
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