Fig. 3From: The identification, approaches to cleaning and removal of a lead-rich salt crust from the surface of an 18th century oil paintingCross-section of sample BMRS4 #2 (blue sky) before varnish removal showing the two varnish layers and the blue paint layer; A Darkfield illumination; B UV radiation; C SEM–EDX spectra of the area identified as the crust and shown by the black arrows in D; D SEM-BSE image of the area shown by the black box in (A) and (B)Back to article page