The project was part of SIK-ISEA’s Fellowship Programme
Synchrotron x-ray microtomography (SRXTM) is a powerful non-destructive technique ideal for high resolution investigation of a wide range of materials. At the PSI in nearby Villigen, the 2.9 T superbend-generated high brilliance photons allow imaging at high energies (above 20 keV) of electronically dense materials, such as those often found in paintings. In this project we have – in collaboration with PSI’s TOMCAT beamline (Tomographic Microscopy and Coherent Radiology Experiments) – pioneered the application of SRXTM to painting studies.
What new information does SRXTM bring that is not accessible with conventional techniques?
Conventional research methodology for paint microsamples can be categorised into one and two dimensional techniques. One dimensional, i.e. bulk material analysis techniques, provide detailed data on chemical composition, but do not give spatially resolved information.
Spatially resolved information (i.e. information on the location and distribution of the different chemical phases) can to some extent be gained through two dimensional, i.e. analytical imaging techniques. Although restricted to a single exposed polished surface of a sample, this approach has proved very useful in the past towards the understanding of chemical processes on or below the picture surface. However, since three dimensional measurements were tested, it has become clear that a two dimensional image is not sufficiently representative for the accurate study of the composition and degradation of paint layers.
The tomograpic data can be studied in a virtual domain in any direction.