Fig. 1

A Michael Sweerts, Peasant Family with a Man Defleaing Himself, c. 1646–55. Oil on canvas, 66.5 × 50 cm. Mauritshuis (The Hague), inv.no. 886. The white rectangular indicates the detail area shown in B. The white circle indicates the detail area shown in C. The red dot indicates the area where the paint sample in E is taken. B Detail showing a shape applied with lighter paint around the mother figure. C Micrograph showing a detail of the face of the mother figure: a narrow aperture in between the paint of the face and the background sky provides a view to the underlying dark grey paint of the halo. D Infrared reflectogram revealing the presence of a carbon-based (thus dark) halo-like underpainting in the area of the light shape. E Microscopic image of a paint sample taken from the area of the halo. Three paint layers are present in this paint sample: (1) the reddish brown ground, (2) the grey paint layer used for the dark halo, consisting of lead white and a carbon black pigment (visually typical of charcoal), (3) the light blue paint layer of the sky, containing lead white, carbon black and a blue pigment (likely ultramarine). Layers 4 and 5 are varnish layers. Images courtesy of the Mauritshuis Museum. Photography by Margareta Svensson. Micrograph by Kirsten Derks. Infrared reflectogram made by Sarah Kleiner. Microscopic image of the paint sample made by Carol Pottasch