I have profited from discussion, correspondence and in some cases collaboration with Shotaro Akaho (National Institute of Advanced Industrial Science and Technology), David Andrzejewski (University of Wisconsin), Michael John Angel (Angel Art Academy, Florence), Irina Artemieva (Hermitage Museum), Anna Bentkowska-Kafel (Kings College London), Rachel Billinge (National Gallery London), Soma Biswas (University of Maryland), Stephanie Buck (Frei Universität Berlin and Courtauld Institute), Edwin Buijsen (Rijksbureau voor Kunsthistorische Documentatie), Lorne Campbell (National Gallery London), Keith Christiansen (Metropolitan Museum of Art), Jim Coddington (Museum of Modern Art), Jacob Collins (indpendent artist, New York), Antonio Criminisi (Microsoft Research Cambridge), David Donoho (Stanford University), Andrea DelPozo (University of Illinois, Urbana-Champaign), Tiarna Doherty (Getty Museum), Marco Duarte (Princeton University), Sven Dupré (Ghent University), Sam Edgerton (Williams College), Gary Faigin (Gage Art Academy), Molly Ann Faries (Indiana University), Yasuo Furuichi (Kanagawa, Japan), Jun Fujiki (National Institute of Advanced Industrial Science and Technology) Michael John Gorman (Arkimedia Dublin), John Grievenkamp (University of Arizona), Ella Hendriks (van Gogh Museum), Hideitsu Hino (Waseda University), Peter Humphrey (University of St. Andrews), Vincent Ilardi (University of Massachusetts), Amy Ione (Diatrope.com), Mohammad Irfan (Stony Brook University), Eija Johansson (Chalmers University, Sweden), M. Kimo Johnson (Massachusetts Institute of Technology), Tadeusz Jordan (City University of New York), Hee-Tae Jung (Stanford University), Fredrik Kahl (Chalmers University, Sweden), David Kale (Stanford University), Martin Kemp (Oxford University), Thomas Ketelsen (Kupferstich Kabinett Dresden), Alexander J. Kossolapov (Hermitage Museum), Ashutosh Kulkarni (Stanford University), Yubin Kwang (Lund University), Wolfgang Lefévre (MPI für Wissenshaftsgeschichte Berlin), David C. Lindberg (University of Wisconsin), Xu Liu (Ricoh Innovations), Christof Lüthy (Radboud Universiteit Nijmegen), Walter Liedtke (Metropolitan Museum of Art), Ann James Massey (Independent painter, Paris), Sean Meador (Stanford University), Pamela O. Long (American Association of Historians), Noboru Murata (Waseda University), Gabor Nagy (Sony Entertainment Research America), Petria Noble (Royal Kabinett of Paintings Mauritshuis), Elke Oberthaler (Kunsthistorisches Museum Vienna), Lynda Pigeon (Barley Hall Museum, York UK), M. Dirk Robinson (Skybox Imaging), Monique de Ruette (Musées Royaux d'Art et d'Histoire Brussels), Silvio Savarese (University of Michigan), Sara Schechner (Harvard University), James Schoenberg (J & J Graphics), Morteza Shahram (Stanford University), John Spike (Independent scholar, Florence), Brandon Smith (University of Wisconsin), Will Smith (York University, UK), Ron Spronk (Queen's University), Philip Steadman (University College London), Marja Stijkel (Rijksmuseum), David Stone (University of Delaware), Richard Stone (Metropolitan Museum of Art), Marie Ström (Chalmers University, Sweden), Timothy Stotz (Studio Escalier), Yvonne Szafron (Getty Research Institute), Richard Taylor (University of Oregon), Christopher W. Tyler (Smith-Kettlewell Eye Research Institute), Yumi Usami (Waseda University), Pico van de Werken (Independent painter, Amsterdam), Ramon van de Werken (Independent painter, Amsterdam), John Varianno (Mt. Holyoke College), Robert Wald (Kunsthistorisches Museum and Liechtenstein Museum), Elizabeth Walmsley (National Gallery of Art), Nicholas Williams (Independent painter, UK), Karsten Wirth (Independent painter, Germany), Lisa Wong (Sony Entertainment Research America), Li Zhang (University of Wisconsin), Zhigang Zhu (City University of New York), as well as students in my classes ART216A, "Optics, perspective and Renaissance painting," and CS379D, "Computer vision and image analysis in the study of art," at Stanford University. I also thank the Getty Research Institute for Extended Reader's Privileges at their superb collection of reference materials. The views and analyses in this site and linked papers are those of their authors and may or may not reflect the views of individuals just listed.