Other
Color Theory and Mixing: 16 Lessons in Color Theory
Complete site on using color in art. Includes the history of color, psychology of color, color perspective, and how color changes depending on the medium used. Includes activities to help understand how to use color in your art.
PBS
Pbs: Hans Hofmann for Teachers (Lesson Plans)
Go directly to the lesson plans developed as complements to the PBS documentary "Hans Hofmann: Artist/Teacher, Teacher Artist." These classroom resources were designed to explore the influential theories of the artist.