Prof. Dr. Christoph Herm
Archaeometry and Science in Conservation
Dresden Academy of Fine Arts

The project aims at the chemical analysis and material scientific characterization of the polychromy of the sculptures and adjacent architectural surfaces and its carriers. The investigation shall be carried out as far as possible by means of non-destructive Raman spectroscopy. It is possible to acquire a mobile Raman microprobe within the project. These measurements shall be complemented by other non-destructive methods as well as modern analytical methods in the laboratory using selected samples.
Additionally, particular problems are: “Limits and scope of in-situ measurements on polychrome sculptures using a mobile Raman microprobe” as well as “Evaluation of in-situ methods in contrary to laboratory methods and development of a protocol for non-destructive investigation of polychrome sculptures”.
Head of the project is Dr. Christoph Herm, professor for archaeometry and science in conservation at Academy of Fine Arts in Dresden (Hochschule für Bildende Künste Dresden). The investigations shall be carried out by a PhD student. The supervision is implemented in cooperation with Eike Brunner, professor for bioanalytical chemistry at Dresden University of Technology (TU Dresden).

In the sub-project “Natural Sciences” Jacqueline Menzel studies the scopes and limits of a mobile Raman microprobe. With this device she identified several pigments of the medieval colour palette at the sculptures of the West Choir in Naumburg Cathedral definitely. Some problems appeared measuring green or blue layers. These obviously absorb the red laser beam and did not result in distinct Raman spectra. Therefore microprobes and cross sections taken by the conservators are investigated under the Raman microscope at the laboratory of the HfBK Dresden. In addition, complementary methods for identifying pigments, lakes, leaf metal applications and binders are applied. Investigations at the medieval polychrome sculptures in Cologne Cathedral delivered further information about the usage of the mobile Raman microprobe.