A couple of my favorite art terms have to do with light/shade:

chiaroscuro is defined as the technique of modelling volume by strongly contrasting light and shadow -- think Rembrandt and Rubens and check out this David http://www.metmuseum.org/collections/view1zoom.asp?dep=11&full=1&mark=1&item=49.7.21.

and sfumato (yes, that's spelled right) is the technique of blurring and softening lines to create a hazy or smoky effect. Popular with Renaissance guys like Leonardo http://www.hermitagemuseum.org/html_En/03/hm3_3_1b.html and Coreggio.