http://www.ncsa.uiuc.edu/SDG/Experimental/anu-art-history/prints.html
This site presents an interactive student tutorial on the history of prints and printmaking. This project has more than 2,800 digitized images, ranging from the 15th century to the 20th century, from religious to secular, from 'high art' to popular art. It also includes sections on about printing techniques (mezzotint, engraving, monograph, etc.), using extreme closeups of the prints selected. All images are in JPEG format, for compactness, although many of the prints are monochrome. The collection will eventually be joined by relevant art-historical texts and commentaries.