Conservation project by the DFG at the HAWK
Scarcely decipherable and subsequently altered fragments of medieval wall paintings repeatedly confront us with the question: how can we make them accessible to science, as many interested people as possible, and preserve them sustainably? In May 2022, the German Research Foundation (DFG) approved a project proposal from HAWK by Prof. Dr. Ursula Schädler-Saub, co-applicant Dr. Angela Weyer, on this topic. Work will start on 1 September, together with the two project partners, the Cathedral Abbey of Brandenburg and the Brandenburg State Office for the Preservation of Historical Monuments and the State Archaeological Museum (BLDAM), in tandem with the Chair of Conservation, Art Technology and Conservation Science at the Technical University of Munich (TUM). Many external experts and specialist institutions are involved in the project, including the Fraunhofer IFF in Magdeburg and Cologne Game Lab.
The HAWK team - here, the restorer Sabine Krause-Riemer M.A., who specialises in digital techniques, should be mentioned - wants to further expand the possibilities of hyperspectral examination methods on fragmentary medieval wall paintings and their digital visualisation in interdisciplinary cooperation with other experts and institutions. In doing so, the researchers will tie in with the project headed by Prof. Dr. Ursula Schädler-Saub, which was successfully completed at the end of December 2021 and was also funded by the DFG. The project was dedicated to the mural painting cycle on the sciences and the arts in the former library of the Cathedral cloister in Brandenburg and its substantive and ideational indexing, in collaboration with art historians at the University of Paderborn (led by Prof. Dr. Ulrike Heinrichs). Particularly worthy of mention here is the combined application of several radiation-diagnostic and imaging procedures, with which the areas of a painting that are barely or not at all visible to the naked eye become more visible again. The resulting visual phenomena, collected in so-called image stacks, are evaluated in order to then obtain a formative interpretation based on the findings in interdisciplinary collaboration (see Figs.). This allows conclusions to be drawn about iconography, composition and stylistic features.
The procedure is explained by the example of the wall painting in the Cathedral cloister in Brandenburg (see Fig.). The hybrid mapping programme metigo®MAP was used to evaluate various radiation diagnostic imaging methods to improve the readability of fragmentary wall paintings. The individual images of HSI, MSI, DStretch and Makro, which are located on different levels, can be activated or hidden as required. This simplifies the evaluation and recording of structures that stand out ("delimitable phenomena"). The traces of outline and interior drawings, of surfaces whose silhouettes stand out against other surfaces, are graphically captured as lines and surfaces in the case study presented here. The results achieved in this way were discussed in the interdisciplinary team, combined with a critical evaluation of the possibilities and limitations of this method. A distinction was made between confirmed and interpretative data based on analogies; these are marked accordingly in the graphical representation (see legend). The selected example shows a section of the dance scene from the depiction of the Theatrica, in the upper area of the north wall of bay 9, former library on the 1st floor of the north wing of the Cathedral cloister at Brandenburg (wall painting dates to the 1440s).
An important objective of the new DFG project is to evaluate and refine the largely non-invasive techniques developed for this purpose, and also to make them even more practical and user-friendly. This should enable innovative insights into fragmentary medieval wall painting also on less famous cultural monuments, and not only within the framework of large-scale research projects. In addition, scientifically sound models for communicating these findings to a wider audience are to be developed, using augmented reality and 3D simulation, with a clear distinction between real existing findings, additions based on analogies and "narrative" elements.
On the basis of further case studies of fragmentary wall paintings of the late Middle Ages in the former Brandenburg bishop's residence Burg Ziesar and in the abbey of Kloster Zinna near Jüterbog, the methodology developed will be tested and evaluated under the different conditions given there (with regard to the historical materials and techniques, to earlier revisions and the present state of preservation). As in the Brandenburg Cathedral cloister, important insights into the complex pictorial programmes and their artistic realisation as well as into the functional history of the painted rooms can be expected based on technical painting and radiation diagnostic examinations as well as imaging procedures.
A methodological and technical optimisation of the "digital toolbox" developed in this way is to be carried out on the broader basis of scientific investigations than before, with the use of further state-of-the-art equipment and technical possibilities, in close cooperation with the Fraunhofer IFF Magdeburg (Dr Andreas Herzog) and the TUM. This "digital toolbox" is designed for use in interdisciplinary projects for research on cultural heritage, integrating various procedures and research methods. In its continuation, it will also be done for "low budget" projects in heritage conservation because it enables an initial "coarse-meshed" overview investigation with non-invasive methods and thus findings on the basis of which decisions can be made about further questions and a differentiated, substance-preserving approach.
Title of the DFG project
Title of the DFG project at HAWK: "Hyperspectral examination methods and the development of a digital toolbox for researching and communicating fragmentary wall paintings". Project Manager: Prof. Dr. Dipl. Rest. Ursula Schädler-Saub, Faculty of Architecture, Engineering and Conservation; research assistant at HAWK, Faculty of Architecture, Engineering and Conservation: Dipl.-Rest. Sabine Krause-Riemer M.A.; specialist involved in aspects of knowledge transfer and mediation: Dr. Angela Weyer, Head of the Hornemann Institute at HAWK. Project duration: 3 years.
Title of the DFG project of the TUM (Tandem project): "Development of a methodology for the non-destructive examination of wall paintings in situ: the palimpsest of the Magdalenenkapelle of St. Emmeram, Regensburg". Project leader Dr. Clarimma Sessa, materials scientist and research associate, TUM; project group: Prof. Dr. phil. Dott. Thomas Danzl, Chairholder, Chair of Conservation, Art Technology and Conservation Science, TUM School of Engineering and Design; Nadia Thalguter M.A., PhD student and research assistant, TUM. Project duration: 3 years.
DFG predecessor project
Reference to the publication on the DFG predecessor project:
Ursula Schädler-Saub and Mechthild Noll-Minor (eds.): Der Wandmalereizyklus zu den Wissenschaften und Künsten in der Domklausur zu Brandenburg - Interdisziplinäre Erforschung und Visualisierung des fragmentarischen Bestandes (Schriften des Hornemann Instituts Bd. 22, ed. by Angela Weyer), Berlin 2022.
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