Fig. 6
From: Jan Steen’s ground layers analysed with Principal Component Analysis
a The Tooth-Puller, 1651, oil on canvas, overview with cross section location marked with yellow x. b Cross section shown in bright field, layers 1–3 are the ground layers. c Cross section shown in UV. d Backscatter electron image at ×500 magnification. e–g Elemental mappings of different elements, indicating the presence of chalk, lead white and umber