This Web site, developed by the Exploratories Project at Brown University, provides a series of applets to help users understand the various concepts in Color Theory. In the combined Color Mixing applet, undergraduate and high school students can discover how lights, paints, and filters interact. Users can learn about the properties of incoming light, frequency, and reflectance. The site also provides activities for metamers, Triple Cell Response, and much more. Anyone seeking help with color concepts will benefit from this educational, interactive Web site.