1. National Gallery of Art, Washington, DC 20565, USA
2. Departments of Art Conservation and Electrical & Computer Engineering, College of Arts and Sciences, College of Engineering, University of Delaware, Newark, DE 19716, USA
3. Hydrosat, Washington, DC 20036, USA
4. Centro per la Conservazione ed il Restauro dei Beni Culturali “La Venaria Reale”, 10078 Venaria Reale (Turin), Italy