In January 2021, a team from the University of Antwerp (the AXES and ARCHES research groups) conducted a series of new investigative tests in the Groeningemuseum on the painting 'Madonna with Canon Joris van der Paele' by Jan van Eyck. The researchers made use of a new scientific technique that they had developed themselves: Macroscopic X-ray Powder Diffraction Scanning (MA-XRPD).
Back in 2015, the University of Antwerp also conducted research into this same painting, using a different scientific technique: Macroscopic X-ray Fluorescent Scanning (MA-XRF). This makes it possible to identify the presence of specific chemical elements in the painting, such as lead, copper or mercury. This in turn makes it possible to establish what kinds of pigment were used by Van Eyck and also where more recent overpaintings were carried out. However, some chemical elements – copper is a good example – can form numerous different compounds, which can be included in different kinds of pigments. With MA-XRF, it is not possible to say with certainty which pigment is which.
However, this is possible with MA-XRPD. The new technique – based on the use of x-rays– allows researchers to distinguish between different chemical compounds. A fine beam of rays is projected onto the painting, where they interact with the substances present in the paint, before being deflected and reflected back. The reflected beam has a unique pattern for each kind of crystal structure. In this way, it is not only possible to identify specific pigments, but also the processes of degradation and where overpaintings have been carried out over the years.
Scanning with this technique takes a lot of time. For this reason, only a limited number of small areas on the painting were investigated, about which questions already existed. One of these questions related to lead white. In the 'Ghent Altarpiece', the MA-XRPD scan discovered different kinds of lead white. The new research in the Groeningemuseum was intended to establish, amongst other things, whether or not Van Eyck used the same lead white for the painting of 'Madonna with Canon Joris van der Paele' as he did for the 'Ghent Altarpiece'. Other important questions related to the use of ultramarine, a very expensive blue pigment, and the type of green used for the parrot and the canopy behind the Madonna. In the video below, you can find out what the researchers discovered.
This research contributes to a further deepening of our knowledge about our collection. On the one hand, it provides new insights into the materials and methods used by the artist. On the other hand, it reveals valuable information about the change processes in the different layers of paint, so that, where possible, remedial action can be taken quickly and effectively.