Seeing Inside Written Artefacts in 3D

Project Group 3

The project group ‘Seeing Inside Written Artifacts in 3D’ aims to to employ X-ray analytical methods to study the diverse internal structure of written artefacts. Learning about the material properties of the diEerent writing media such as clay, wood, cartonnages, parchment, paper or even stone, sheds light on their natural environment, provenance, and fabrication techniques.

Written artefacts are rarely permitted to leave the secure environment of museums, so it is often necessary to develop mobile analytical tools to investigate these precious objects on site. Over the past few years, we have therefore developed a transportable, high-definition X-ray scanner for computed tomography, named ENCI (Extracting Non-Destructively Cuneiform Inscriptions). This device has been specially optimised for 3D analysis of cuneiform inscriptions and enables us to examine enclosed cuneiform tablets non-invasively and read the hidden inscriptions inside. Since ENCI is a modular device composed of eight separate parts, it is portable and can be assembled on site. This has enabled us to carry out diEerent measurement campaigns at the Louvre in Paris (France), the Museum of Anatolian Civilisations in Ankara, the Archaeological Museum in Kayseri (Turkey), and the Frau Professor Hilprecht Collection of Babylonian Antiquities in Jena (Germany). Beyond reading hidden texts, these experiments also showed that a wide range of material properties can be extracted from X-ray tomographic data. These include, for example, inclusions in the clay that sometimes indicate the presence of organic materials or details of the manufacturing process.

This project group focuses on the operation of ENCI and extends its usage to investigate a variety of written artefacts to shed light on their inner 3D structure. By adding analytical techniques to complement the tomographic data, such as X-ray diEraction (XRD) and X-ray fluorescence (XRF), we can conduct a more detailed analysis of the materials to gain a clearer picture of their properties. Hard X-ray diEraction, for instance, could reveal details about the clay's composition and mineralogy. Text and material properties can then be linked to improve our understanding of the broader context of cuneiform writing on clay during a given period. For example, the composition of the clay might indicate the provenance of a letter — information that is rarely specified in the text — and thus provide fundamental clues for reconstructing history. Moreover, the tomographic data from the analysed artefacts can be used to produce 3D prints that can serve as educational materials for students and the general public at science festivals and exhibitions.

Another main objective of this project group is to compile a reference database that showcases the structural diversity of written artefacts, which will be made available to the wider scientific community. This may help to improve future investigations of such delicate objects. As investigations must be non-invasive, eEects of X-ray radiation damage will be systematically investigated in order to define tolerable dose thresholds that ensure the preservation of cultural heritage artefacts.

In collaboration with the Mobile Lab at the CSMC, these activities will be complemented by other analytical techniques, such as XRF and FTIR, for surface-sensitive analyses. Furthermore, we aim to develop X-ray phase-contrast imaging (XPCI) in a laboratory environment using another X-ray imaging platform at DESY. This will enable us to visualise hidden text based on carbon-based inks that are usually invisible to absorption-based X-ray microscopy.