Other
Guidance/the Alphabet of Art/value
An informative site that explains Value as an element of art using examples of Rembrandt's work. This is a good juxtaposition between the works "Night Watch," and "The Anatomy Lesson," by Rembrandt.
ArtLex
Art Lex: Value
Artlex's definition of value and how it applies to black and white and color in art. There are links to other sites to further explain the term and also related terms to explore.
University of Saskatchewan (Canada)
University of Saskatchewan: Value & Color
Basic color theory is discussed in relaton to computer art applications. Illustrated.
Other
Guidance Communications: The Alphabet of Art
A site dedicated to providing vocabulary for the elements of visual design. Includes a visual notation system for describing both the elements and attributes of art.