Cornell University
Cornell University: Art, Design, and Visual Thinking
Use the left-hand toolbar of this site to investigate an online textbook for the language of design. It provides visual examples and explanations of line, form, color, color psychology, texture, balance, proportion and many more...
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.