Industrial computed tomography is a non-invasive and non-destructive method of studying the structure of a ceramic and thus also of recognizing additions with almost 100% certainty.[8] While medical CT systems are optimized for the human body and are therefore limited in their display accuracy and penetrating ability, industrial CT can detect inhomogeneities with high precision, penetrate all layers and reliably distinguish between different materials based on their different absorption values. Despite these advantages, the use of CT in archaeological, museum and art historical research is only slowly gaining ground, which is partly due to the availability of the appropriate systems. A seminal pioneering project was carried out in the 1990s at the Allard Pierson Museum in Amsterdam, where the structure of Greek vases was studied using CT.[9] One of the focal points was the most accurate representation of vessel profiles, whereby, in contrast to conventional drawings, the inner contour of the vessel wall could also be recorded precisely. A remarkable result was the distinction between different types of ceramics based on their respective typical gray values, which corresponded to the stylistic assignment to individual artists.[10]

Since these first experiments, the use of CT, among other things, for the archaeometric recording of vessel profiles and wall thicknesses has proven itself many times over. Further pioneering research projects took place in Graz and Vienna.[11] The documentation of historical restorations on two Greek vessels from the Universalmuseum Joanneum is particularly noteworthy. One vessel was identified as an assemblage and the restorer’s procedure reconstructed: individual fragments of different vessels were selected from a larger pool and combined with a supplementary mass to form an overall shape. The different origins of the shards could be clearly recognized by their wall thicknesses and degrees of brightness in the CT.[12] A thin varnish had led to a dark surface coloring and an optical leveling of the shards and the supplementary mass, so that the manipulations were difficult to recognize from the outside.[13] On another vessel, among other things, modern overpainting could be documented based on the higher density of the paint used.[14]

Several works dealt with the radiographic analysis of production techniques, whereby it could be shown, among other things, that the arrangement and orientation of air bubbles allowed conclusions to be drawn about the construction method used in each case (e.g. production on the potter’s wheel, beading technique, etc.).[15]

The non-invasive nature of the CT naturally helps in a special way with questions that would otherwise require irreversible damage to the objects. At the Hebrew University in Jerusalem, for example, clay containers for cuneiform tablets were examined using medical CT, which until then had to be broken up according to previous documentation in order to study their contents.[16] CT can also provide important information for assessing the stability and damage pattern of objects and thus for conservation work.[17]