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Topic: pigments (3 msgs / 96 lines)
1) From: Kevin DuPre
With all due respect, organic substances such as
coffee are generally not referred to as containing
pigments.
Pigments are typically, though not always, chemical
substances added to a neutral base such as Gum Arabic
(in the case of designer's gouache) to make a paint
which approximates the color of an organic or
inorganic object or from which an approximation of
such object color can be obtained from mixing.
An example is cobalt blue, cadmium orange or cadmium
yellow (all of which contain chemical substances,
which by the way are carcinogenic if ingested or
inhaled). 
Not all pigmentation is permanent, and in the
art/illustration world impermanent colors are
typically referred to as fugitive. Why is this
relevant to the discussion?
The color of coffee as we all know is naturally
occurring resulting from carmelization and
carbonization of sugars and starches in the bean due
to the roasting process. As coffee is an organic
compound and oxidizes upon exposure to
oxygen-containing air, I would consider that
highly-fugitive.
Considering this, I am pretty certain that the Agtron
disks do not contain the naturally occuring substances
which result in the brown-ness(sp?) of roasted coffee.
If they were, they would shift in color over time and
upon exposure to oxygen.
I believe the production cost of the disks largely is
a result of the permanency of the colors, the
stabilized nature of the substrate upon which they are
painted (if indeed it is a paint), and the highly
precise quality assurance controls used to insure that
the colors match the spectrophotometric measurements
of the same values produced by the machine.
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--
Kevin DuPre
obxwindsurfhttp://profiles.yahoo.com/obxwindsurf"The real voyage of discovery consists not in seeking new landscapes but in having new eyes -- Marcel Proust"
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2) From: Spencer W. Thomas
Oh, now you're asking for it. :-)
Let me quote briefly from the Oxford English Dictionary:
    pigment
*1. * A colouring matter or substance.
*a. * Any substance (usually artificially prepared) used for colouring 
or painting; a paint, dye, `colour'; in technical use, a dry substance, 
usually in the form of powder or easily pulverized, which, when mixed 
with oil, water, or other liquid vehicle, constitutes a `paint'.
*b. * Nat. Hist., etc. Any organic substance occurring in and colouring 
any part of an animal or plant; the natural colouring-matter of a tissue.
I submit that meaning 1b says precisely that "organic substances ... 
contain pigments"
=Spencer
Kevin DuPre wrote:
<Snip>
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3) From: Dan Bollinger
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I was taught that fugitive colors were colors that bled, i.e. they escaped.
Impermanent colors simply fade away like old soldiers.  ;) Dan
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