CWI scanner revealing art secrets seeks new applications

Dating two wooden book chests that are both attributed to the escape in 1621 of the Dutch intellectual Hugo de Groot; discovering that a 17th-century wooden cornetto (a wind instrument) is made not of one but two types of wood; and making visible the sculptor's fingerprints inside terracotta figurines. These are three striking results that CWI researchers have achieved with the FleX-ray scanner in collaboration with research partner Rijksmuseum.  The FleX-ray Lab contains a special X-ray scanner that went into operation in 2017. The research into Hugo de Groot's book chest even won the NWO Team Science Award in November 2021.

The FleX-ray scanner excels in flexibility, high resolution and in the different types of materials the scanner can see through. "We are developing mathematical methods to scan art objects that are very different in terms of shape, dimensions and materials," says Francien Bossema, PhD student in CWI's computational imaging group, the research group that uses the FleX-ray scanner to develop new scanning methods and smart algorithms. "Both the X-ray source, the detector and the object to be scanned can move in relation to each other. This allows us to adapt each scan to the specific requirements of an art object."

Bossema is also a guest researcher at the Rijksmuseum in Amsterdam, working there with, among others, Erma Hermens, Rijksmuseum Professor of Studio Practice and Technical Art History affiliated with both the Rijksmuseum and the University of Amsterdam. "Thanks to the FleX-ray scanner, we discover things in art objects that we cannot find in any other way," says Hermens. "And these new insights in turn raise new questions. This is how we bring art history one step further."

Francien Bossema (l), PhD student at CWI's Computational Imaging group and Erma Hermens (r), technical art historian at Rijksmuseum and UvA. Hermens was recently appointed as the new Director of the Hamilton Kerr Institute and Deputy Director of the Fitzwilliam Museum, University of Cambridge

Hermens sees countless new possibilities for the FleX-ray scanner in the future: "Scanning objects that consist of multiple materials with a construction invisible to the eye is also on our wish list. It would also be very exciting if we could visualise and measure the traces left by tools on an art object in three dimensions. That might reveal something about the type of tool, the making process and maybe even something about the maker."

The successful collaboration that CWI has built up with the Rijksmuseum in recent years is hungry for more, says Bossema. "From CWI we would like to set up more collaborations like the one with the Rijksmuseum. We are already exploring whether the FleX-ray scanner can be used to check the quality of food. For example, scanning vegetables or fruit to see if they have started to rot, or scanning meat to see if it contains anything that should not be there. Because of the speed at which the food passes by on a conveyor belt, scanning food has completely different challenges than scanning art objects.”