Congrats to everyone concerned for this site: really incredible.

Here's the problem. I'm getting old and have taken up modeling. I've messed around with cheap acrylics (enough to know that I'll be painting models with them) and had a gas creating colors. I want to create any color using primes (including white and black natch). I've done a lot more computer graphics than real painting. Can anyone direct me to software, books, or gadgets that would help me create a paint color using RGB code? I know it won't be exact, but ballpark would be great.

Thanks in advance.
Eric