Fig. 1From: Analysis of red chalk drawings from the workshop of Giovanni Battista Piranesi using fiber optics reflectance spectroscopyTwo leaves of the Karlsruhe Albums, showing a selection of the red chalk drawings (Staatliche Kunsthalle Karlsruhe, folios 9 (left) and 10 (right) of Volume 1, Inv.-No. IX 5159-35); photographs: Annette T. KellerBack to article page