Development of a methodology for non-destructive studies of wall paintings in situ: The palimpsest of the Magdalen Chapel of St. Emmeram, Regensburg

该项目的总体目标是制定一种非破坏性的现场检查壁画的方案。将对雷根斯堡圣埃默拉姆马格达伦教堂的独特回文进行研究，以优化方法。勃兰登堡大教堂修道院的壁画已经得到了广泛的研究，将作为一个验证案例进行进一步的调查。对所用材料的鉴定和对其物理化学性质的评估，可以将单独的层分配到特定的绘画阶段，确定后来的干预措施，以及选择适当的保护-修复策略。壁画的材料表征由于其不可估量的价值、复杂的地层以及不同的材料，是具有挑战性的。从分析的角度来看，这意味着在尊重艺术品完整性的同时，尽可能多地获取关于有机和无机化合物的信息。解决这些要求的办法是使用非破坏性、互补性和便携的分析和数字工具。工作计划包括由保护人员结合档案研究和数字文件(摄影测量、紫外线荧光摄影、METIGO®MAP)进行检查。一个双传感器高光谱成像系统(范围400-2500纳米)、一个宏观X射线荧光扫描仪和一个3D数码显微镜将得到及时的分析工具的补充，如用于材料表征目的的便携式拉曼和中红外光谱仪。红外热像仪和太赫兹光谱学将分别用于解决保护问题和调查隐藏的漆层。能够记录空间分辨光谱的成像系统将被用来创建表面上不同元素/化合物的映射。以其他方式无法辨认的图案的可视化对于回答保护和艺术技术方面的问题将是极其重要的。尽管这些方法在文化遗产研究方面具有巨大潜力，但由于成本高、实施耗时和生成的数据复杂，这些方法尚未在实地得到常规应用。该项目的里程碑将是优化现场测量活动的分析方法，为历史材料创建多模式光谱数据库，以及执行便于用户使用的数据处理协议。我们的研究将在保护修复实践中引入最先进的技术。该项目的基础是保护-修复和材料科学之间强有力的跨学科互动。这些发现将确保进一步研究的基础，例如在艺术史领域。马格达伦教堂的壁画也将对普通公众开放和可读。因此，礼拜堂在教科文组织世界遗产雷根斯堡的范围内的知名度将得到提高。

The overall aim of the project is the development of a non-destructive protocol for the examination of wall paintings in situ. The unique palimpsest of the Magdalen chapel of St. Emmeram, Regensburg, will be studied to optimize the methodology. The wall paintings in the Brandenburg cathedral cloister, already extensively studied, will be further investigated as a validation case.The identification of the used materials and the assessment of their physico-chemical properties allow to assign individual layers to a specific painting phase, to identify later interventions, as well as to choose proper conservation-restoration strategies.The material characterization of wall paintings, due to their inestimable value, complex stratigraphy as well as heterogeneous materiality, is challenging. From an analytical point of view, this means to acquire as much information as possible about organic and inorganic compounds while respecting the integrity of the artwork. The solution to such requirements is the use of non-destructive, complementary and portable analytical and digital tools. The work plan includes the examination by conservators combined with archival research and digital documentation (photogrammetry, UV fluorescence photography, metigo®MAP). A double-sensor hyperspectral imaging system (range 400-2500 nm), a macro X-ray fluorescence scanner and a 3D digital microscope will be complemented by punctual analytical tools such as portable Raman and mid-infrared spectrometers for material characterization purposes. Infrared thermography and Terahertz spectroscopy will be applied to address conservation issues and to investigate hidden paint layers, respectively. The imaging systems that are able to register spatially resolved spectra will be used to create mappings of different elements/compounds across the surface. The visualization of patterns that otherwise are not recognisable will be extremely important to answer conservation and art-technological queries. Despite their great potential for cultural heritage studies, these methods are not yet routinely applied in the field due to high costs, time-consuming implementation and the complexity of the generated data.Milestones of the project will be the optimization of the analytical methods for in situ measurement campaigns, the creation of multimodal spectral databases for historical materials and the implementation of a user-friendly data treatment protocol. Our research will introduce state-of-the-art techniques in the conservation-restoration practice. The project is based on a strong interdisciplinary interaction among conservation-restoration and material sciences. The findings will assure the basis for further research, e.g. in the field of art history. The wall paintings of the Magdalen chapel will be legible and accessible also for the general public. The visibility of the chapel in the context of the UNESCO World Heritage Site of Regensburg will thus be enhanced.