Inhalt des Dokuments
Characterisation and Conservation of Paintings on Walls and Sculpture from Nabataean Petra
The Petra project aims at an intense cooperation between archaeological research, methodological innovation and conservation research in order to exemplarily develop methods for the detection, characterisation, conservation and preservation of specific remains of ancient Nabataean paintings on wall plaster and on sculpture. The project is a joint cooperation between Department of Archaeology at the Humboldt University and Institute for Optics and Atomic Physics at the Technical University of Berlin.
Characterization and further development
During our preliminary research at the TU Berlin it was possible to investigate some technical aspects of selected lead and copper based painted samples as well as gilded samples using 2D and 3D Micro X-Ray Fluorescence (XRF) and 2D and 3D Micro X-Ray Absorption Fine Structure (Micro-XAFS) techniques. Out of this preliminary investigation more specific questions stood up in relation to XAFS measurements. One major challenge in such multilayered samples is self-absorption (SA) in confocal fluorescence spectra whether in 3D Micro-XRF or 3D Micro-XAFS. The SA would influence the results accuracy and hence the final interpretation which in the case of our research would influence our conservation materials choice. In our research project we are proposing to develop a simulation programme incorporating SA factor on medium thick sample systems supported by a validation test on cultural heritage samples. This method can be used for developing spectral analysis methods in applied physics.
Materials science and developing a novel conservation material
Wall painting fragments with copper and lead based pigments have shown various deterioration phenomena. Chemical characterisation of various alteration products is aimed in this research. Accordingly, a proper conservation material and methodology will be suggested and performed. Gilded samples investigated non-destructively with 2D and 3D Micro-XRF showed interesting scattering features which are challenging to interpret in relation to original gilding technique and gold leaf loss. Further research on this front is to take place during this project. Complementary analytical techniques such as optical and electron microscopy are part of our examination approach.
Understanding the nature and mechanism of chemical alteration of copper and lead pigments in the context of our samples as well as the loss of adhesion bond between gold and the layer beneath is a major aim in our project. Based on this approach we are aiming to develop a novel conservation material targeting gilded wall painting samples as a novel model for Scientific Conservation connecting materials science and conservation. Specialists from the various fields will be able to intensively collaborate in situ in Petra as well as in Berlin.
Point of contact: Maram Na’es-Lühl