RE: Metamerism
RE: Metamerism
- Subject: RE: Metamerism
- From: "Fred Bunting" <email@hidden>
- Date: Thu, 1 Nov 2001 13:16:26 -0800
- Thread-topic: Metamerism
Bruce J. Lindbloom restates the case in question:
>
Comparison 1: Monitor color matches print color when print is
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illuminated
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with light source "A".
>
>
Comparison 2: Monitor color does not match print color when print is
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illuminated with light source "B".
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>
Whether or not there is a match in Comparison 2 neither
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proves nor disproves
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any hypothesis about the nature of the match in Comparison 1
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(metameric or
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spectral). This is because the monitor color is neither formed by nor
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influenced by the light source used to view the print.
It is true that I should have looked at the specific case more closely.
However, I should point out that Comparison 1 by itself is not
sufficient to demonstrate that the match is due to the effect known as
metamerism.
There are two possible explanations for the match in Comparison 1:
A) Metamerism: the two spectra ... the spectrum produced by the monitor
and the spectrum produced by the specific combination of print and
illuminant ... are different, but somehow produce the same tristimulus
response in the eye.
B) The two spectra actually happen to be identical. This is not
metamerism.
Nevertheless, I have to concede your point ... Comparison 2 does not
help the situation. It does not help you determine whether hypothesis A
or B is the correct one to explain the result of Comparison 1. Why?
Because the effect of the illuminant changes the spectrum from the
print, but does not affect the spectrum from the monitor color. So
Comparison 2 is a fundamentally different experiment than Comparison 1.
In fact, I don't believe there is any experiment, short of using a
spectroradiometer, to determine whether A or B is the case. Therefore
one could argue that case B is just about the pedantic definition of
metamerism, and has no practical value. If one cannot distinguish
between cases A and B using real-world observational experiments, then
it's not worth considering.
Good point.
Fred Bunting