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.
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.