The aim of the chair is to conduct research into the use of powerful, newly developed imaging methods for the study of paintings, as well as to provide services and eduction in this field. For the latter, the chair intends to familiriase art historians, curators and conservators with these innovative imaging techniques, both in a theoretical and practical manner. To do so, a collaboration if anticipated between the University of Antwerp (Chemistry and Conservation Department) on the one hand and the KIK-IRPA, the KULeuven, and Belgian museums on the other hand.
As early as the beginning of the previous century, several forms of electromagnetic radiation such as ultraviolet, infrared and X-ray radiation are used for the study of paintings. The radiation is employed to gain insight into the hidden and often very complex layer system that hides behind the visible paint surface. This insight is vital for three groups:
- art historians who study the genesis of works or the studio practice of specific artists,
- restorers who are faced with specific conservation issues (eg. Flaking paint layers) and
- staff and curators of museum galleries who try to keep the painting in the best possible conditions for future generations.
Thanks to recent technological developments, including the introduction of sensitive digital sensors with an increasing wavelength range, the efficiency of traditional image techniques such as X-ray radiography and infrared reflectography is increasing. In addition, a completely new technical development occured in the last few years, in particular the introduction of so-called 'analytical' or 'chemical' imaging techniques. Instead of directly registering the radiation that is relflected by or transmitted through the artwork, the radiation is first analyzed by means of spectroscopic techniques. In a next step, the resulting digital data is converted into one or more images by means of software. In concrete terms, the added value of this method is to found in the fact that it provides information about the materials present on and below the entire paint surface in a visual manner, and this in a non-contact/non-destructive manner.
This new method was introduced in 2008 by the AXES research group of the University of Antwerp in collaboration with Delft University of Technology. After an initial proof-of-concept in the particle accelerator in Hamburg (DESY), the technique was soon translated into a mobile device that uses macro X-ray fluorescence (MA-XRF) to scan complete paintings in the museum gallery or conservation studio, without the need to transport or sample the artwork. As the figure above illustrates, the final result is a series of images each showing the distribution of a specific chemical element (iron, copper, lead, etc.). Whereas a conventional radiography generates only one image in which all information is compressed, MA-XRF scanning produces a series of images, one for each chemical element. The figure shows how in this case a portrait of a peasant woman painted by Vincent Van Gogh was re-imaged. The overpainted image shows a strong stylistical resemblance with other studies of farmers that Van Gogh painted in the winter of 1884-'85 in preparation for his first tableau 'The Potato Eaters'. In addition, thanks to this experiment we see immediately which materials Van Gogh used for realizing this study portrait and where these are located exactly in the painting. Unlike traditional chemical point analysis, MA-XRF scanning converts numerical and spectral data into images that are easily readable by conservators. Briefly, one can therefore say that this innovative research method succeeds in combining the visual aspect of the existing imaging methods with the advantages of spectroscopic analysis.
The relevance of this innovative imaging method was quickly evidenced by the interest taken by museums and conservators worldwide. In a few years, more than a hundred works were studied in various European museums (including the Mauritshuis, the Van Gogh Museum, the Louvre, the Gemäldegalerie Berlin, the KMSKA, the KMSKB and recently in the conservation workshop of Ghent Altar Piece) and US institutions (including the MoMA and the Metropolitan Museum in New York City and the J. Paul Getty Museum in Los Angeles). In addition, National Geographic Channel devoted his first 'Belgian' documentary to this topic, entitled: 'Behind the science: hidden masterpieces (see youtube: http://www.youtube.com/behindthescience). The success of MA-XRF scanning prompted both the AXES research group and foreign groups to intensify their research into new scanning techniques.
In addition to this development in the field of X-ray imaging, a number of other important improvements occur regarding the imaging of paintings by means of visual and infrared light. All these so-called "hyperspectral" imaging methods provide much more information than traditional methods from which they are derived, but these techniques have yet to find their way into the daily practice of art historians, curators and conservators. In view of these future developments, it seemed appropriate to develop three types of acitivities within this chair: education, research and service.