In article ,
Dale wrote:
My Uncle is an artist

I have ten years work experience as an imaging system engineer

I was always under the impression that CMY were the color complements or
opposites of RGB

In printing, that is definately true--cyan is the absence of red, magenta
is the absence of green, and yellow is the absence of blue.

he and apparently many others use a color wheel where the are other
complements or opposites to RGB

http://en.wikipedia.org/wiki/RYB_color_model

Artists tend to think of red, yellow and blue as the primary colors.
And, for some reason, this system works when you are mixing paints.
Red and yellow give you orange, yellow and blue give you green, and
red and blue give you purple. Three primaries + three secondaries
give you six basic colors, seen on the pride flag, most non-technical
color wheels, and cartoon depictions of rainbows. Personally, I find
the artist's color wheel with red, yellow and blue equally spaced more
aesthetically pleasing than the RGB color wheel. Anyway, on the artist's
color wheel, the complimentary pairs are red-green, yellow-purple, and
blue-orange.

does anyone know why this situation is? are there two rights or is
someone wrong?

Artists came up with this color system long before the physics of color
vision were understood, so it is not surprising that they identified
a different set of primaries. I wouldn't call it "wrong", either. To
me, green "looks like" a mixture of blue and yellow, while yellow does
*not* "look like" a mixture of red and green. Of course, this could be
a cultural bias implanted back in pre-school, I don't know.

--
"Remember when teachers, public employees, Planned Parenthood, NPR and PBS
crashed the stock market, wiped out half of our 401Ks, took trillions in
TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in
bonuses, and paid no taxes? Yeah, me neither."