X-radiographic analyses of large canvas paintings by Paulus Potter, and the enlargement of The Bull

Six monumental paintings by the Dutch animal painter Paulus Potter (1625–54) were examined using X-radiography to determine how his canvases were prepared, stretched and sometimes enlarged. The digitised X-radiographs were subjected to computer-assisted canvas analysis, using algorithms that produce thread density and thread angle maps. This characterised the types of supports that Potter used, the width of the fabric, how they were stretched onto wooden strainers, and which ground layers were applied. These features distinguished the two types of support. Canvases he used in his early career around The Hague (ca. 1647–51) share features that connect their preparation closely to Potter’s studio. The Bull (1647) was enlarged by the artist during the painting process. After moving to Amsterdam (1652–54), Potter employed exceptionally wide pre-primed canvases. Data from X-radiographs were complemented by analyses of cross-sections containing ground layers, and microsamples of canvas fibres from two paintings.