We review Ketelsen et al.’s discovery of tiny pinprick holes in Jan van Eyck’s silverpoint study portrait of Niccolò Albergati(?), which indicate mechanical copying such as by a Reductionszirkel or Proportionalzirkel, rather than by an optical epidiascope. We “re-enact” copying by Reductionszirkel and find (sub-millimeter) fidelity equal to that in van Eyck’s work. We show that Renaissance artists would face significant challenges making and using an epidiascope, which finds no documentary support, including none from scientists, artists or patrons.
© 2004 Optical Society of AmericaPDF Article