Detection of the Fakes

The paintings were subjected to detailed scientific examination by the Coremans Commission. They were examined microscopically, chemically and by X-ray. The paint of all of them was found to contain traces of the phenolformaldehyde resin. Various traces of the original 17th-century pictures, painted over by van Meegeren, were detected by radiography. Cross-sections of the various pictures were taken and photographed to reveal the various paint-layers.

Traces of cobalt blue - an artificial pigment not manufactured until the 19th century - were detected in The Woman taken in Adultery and The Woman Reading Music. This may have been due to adulteration of the very expensive natural ultramarine used as a blue pigment by van Meegeren (as it was by the artists of the 17th century). The matching of the wood fragment found in van Meegeren's studio with the stretcher of the Emmaus was held to be additional proof of the picture being a fake, as was the fact that the left-hand side of the canvas had straight threads, whereas the other three had "wavy" threads, consistent with the pull of the canvas tacks. This seemed to confirm that the left-hand piece of canvas had been removed as van Meegeren claimed. It was concluded that all the paintings examined by the Commission were modern fakes.