“Looking Under the Surface:” MRI in Cultural Heritage

A lecture by Professor Bernhard Bluemich
Director of the Institute of Technical and Macromolecular Chemistry (ITMC)
RWTH Aachen University, Aachen, Germany

The surface is what we see, but it hides the contents behind, which makes up the properties and function of the object. Diagnostic tools from medicine enable the look behind the surface without destroying the object. An important tool of this kind is magnetic resonance imaging. While suitable for imaging the inside of humans, objects of art and value to cultural heritage are often too large to fit the MRI machine or cannot be moved to it. A compact and portable MRI device is the NMR-MOUSE (Nuclear Magnetic resonance Mobile Universal Surface Explorer) . With it depth profiles can be measured through a variety of objects that reveal their stratigraphy and material properties. We have developed this sensor over 20 years ago and, along with colleagues, applied it to study a variety of objects from tire to plastic pipes and tangible cultural heritage. This lecture will introduce the function and use of the NMR-MOUSE by example of studies concerning frescoes in Herculaneum, the tibia of Charlemagne, the Neolithic iceman mummy Ötzi, and master paintings. Current work concerns the optimization of cleaning procedures for paintings, whereby the NMR-MOUSE is a unique instrument to monitor the solvent uptake and drying as well as the associated deterioration of the paint binder resulting from the solvent exposure.