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Re: Color

Yesterday, an eighth grader ask is white was a color. Could someone
please elaborate on the question. I need the opinions for a
colleague.

Herman E. Carl
Portage Area HS
Portage PA


There are two answers to this question.

White is NOT a spectral color, that is it does not have a single wavelength.

White is a color for artists and house painters.

A similar interesting question is "Is purple a color?" Violet is a
spectral and an artistic color. Purple lies in the artistic pallette
between violet and red, and has no wavelength. It is definitely a
color to my eye and brain however.

Color science describes color in terms of three variables, hue
(color), saturation (pink= low saturation, red= same hue, high
saturation) and brightness.

There are, as I recall, 3 different color indexing schemes, the
Munsell being the most predominant in the US. They all agree on
brightness, but some make maximum saturation = 1 for all hues, while
others make maximum saturation different for different hues.

The hues are arranged around a 360 degree circle, and different
schemes split up the colors differently around this circle.

Related to this area is the idea of the chromaticity diagram, a two
dimensional projection of the three color variables. It is
interesting to look at this in terms of "primary" colors. The
chromaticity diagram is roughly, but not perfectly, triangular. By
picking Red, Green, and Blue lights, and mixing these lights, any
artistic color inside the triangle can be matched. There remain
spectral colors that cannot be matched by adding these three
primaries.

I recall that the first color film experiments used two primaries,
such that a somewhat muted rainbow of colors between the two could be
matched.

I started reading about this several years ago when I took some
weaving courses and we were doing a color gamp. It is very visual, so
at least the pictures would be meaningful to eighth graders.
--
Dr. Vern Lindberg 716-475-2546
Department of Physics Fax 475-5766
85 Lomb Memorial Drive
Rochester Institute of Technology Computer Haiku
Rochester, NY 14623
A file that big?
It might be very useful.
But now it is gone.