From: Elihu Shannon (
Date: Tue Mar 12 2002 - 11:21:15 PST

Dear Sirs
I've already written to you once but didn't get a proper answer.

My question concerns the ability of a pigment to change the colour of,
say, a piece of plastic, even though the number of molecules of pigment
are only 1% or less of the whole piece. How can the pigment be so
effective? After all, for every photon reflected by the pigment, a
hundred others are reflected by the rest of the plastic. It must be at
most 1% I think, otherwise the plastic wouldn't be the same for
different pigments: the plastic keeps its properties for all colours
Anyone with a good answer, please e-mail me at:

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