Chemical Imaging is an umbrella name for a series of recently developed analytical methods that allow identifying the constituting materials of artworks and their degradation products, both at and just below the surface. In contrast with traditional point analysis, during chemical imaging, a very large number of adjacent spots are measured on an object or sample, in 2D or 3D mode. In this way significant areas can be chemically characterized as a whole, instead of just a few discrete spots.
The added value for the heritage field is that it basically translates complex chemical data into images that can be interpreted by non-chemists. The results are number of images, each showing the distribution of chemical elements or species over the surface of an object or sample. In this way, conservators, curators and art historians can intuitively link the features that they visually observe on the surface (e.g. paint strokes, defects, etc.) with chemical composition, hence obtaining entirely new insights on the materials, structure, layer build-up and degradation phenomena of the objects they are studying.
The ARCHES research group collaborates intensively with the AXIS group (Department of Physics, Prof. Koen Janssens) to develop innovative methods for chemical imaging, both at the macro scale (with scanners, operating directly and non-invasively on artworks in museum galleries) as on the sub-micron scale (on minute sample material, extracted from the object).
The introduction of mobile MA-XRF and MA-XRPD scanners for in situ use, as well as advanced experiments in particle accelerators on samples has resulted in various breakthroughs in the conservation and art historical study of heritage objects. In the past these techniques have provided information with unprecedented detail, that appeared invaluable for conservators (steering the treatment of key works of art) while new insights in the genesis and compositional changes of paintings under study prompted art historical scholars to reconsider the appraisal or interpretation of paintings. Finally, these technical advances supplied heritage scientists with tools to better evaluate the effect of innovative cleaning treatments on heritage objects, and gave rise to various dedicated research projects, as illustrated here.