Actually we're both right (in our own communities). Many sets of three colors spaced more or less equally around the color wheel can be used as primaries (ie, colors from which others are made). Here are some examples.
Anybody that mixes pure light sources (eg, physicists, computer color monitors & computer graphics people, TV cameras and picture tubes, etc.) uses RG&B as the primaries from which they make all other colors. These are called the "additive" primaries.
People doing work that is eventually going to involve printing an image (ie, with ink) use cyan, magenta, yellow and black (CMYK) as their primaries from which they can make other colors. These are called the "subtractive" primaries.
What I had forgotten was that artists use neither of these sets. They use RYB, exactly as you said, as their primaries, and they probably have been doing it that way since the days of Red Ochre on cave walls, not knowing a thing about photons and wavelengths.
Group hug! [img]smile.gif[/img]
FWIW, here's a link that probably has more than any normal mortal would ever want to know about color:http://www.awwm.com/fp98tutorial/html/color.htm
Tom / PM[ April 30, 2002, 02:08 PM: Message edited by: PhysicsMan ]