Gamut Tools

I have been really interested in learning about color this past year and have done so via James Gurney's book Color and Light.  I can't recommend this book enough for those of you who want more information on the subject of color and light interactions.  In his book he talks about gamuts, which are a limited range of colors selected via a polygonal mask over a color wheel.     

Below is a really handy online tool to help with setting up your gamut.  

http://www.livepaintinglessons.com/gamutmask.php