Characterisation and Conservation of Paintings on Walls and Sculpture from Nabataean Petra
Physical Chemistry of Solids and Surfaces, Material Characterisation
Final Report Abstract
For the first time an interdisciplinary project, covering archaeology, conservation science and analytical science, was established to aim for conservation of paintings on walls and sculptures from Nabatean Petra. The work was carried out by natural scientists from the TU Berlin, archaeologists from the HU Berlin and conservators from the CICS at the Cologne University of Applied Sciences. Over five research campaigns, the wall paintings in the Petra Archaeological Park were surveyed and documented on-site. Detailed non-invasive optical and analytical investigations were undertaken on selected wall paintings at the villa of ez-Zantur IV, the cave complex in Wadi as-Siyyagh, and excavated sculpture finds from Umm al- Biyara. The research focused on the historical painting techniques, environmental assessment, and the condition of the Nabatean heritage. For material analysis, portable non-destructive methods were applied and complemented by laboratory analysis off-site. The research allowed for the characterisation and digital reconstruction of Nabataean wall paintings schemes. The wall paintings investigated revealed colourful and complex geometrical pattern designs (opus sectile) interwoven in fictive architectural elements. Secco and fresco (and mixed fresco-secco) techniques were recorded. Sometimes, up to six plaster layers were applied onto either hewn rock or masonry. Different incision techniques in combination with underdrawings were applied to layout the design. The analysis revealed the use of a rich palette of pigments such as chalk, white lead, lead red, red ochre, vermillion, Egyptian blue, Egyptian green, arsenic yellow and pigment mixtures such as Egyptian blue with green earth, red ochre with charcoal, vermillion with red lead/white lead. Similarly, a rich use of pigments was also found in the sculpture from Umm al-Biyara. The rich Nabataean gilding of plaster and stucco applications was systematically studied for the first time. Experimental gold conservation materials were successfully prepared and characterized to conserve historical gold layer in a phenomenon-material-specific approach using nondestructive X-Ray testing methods used innovatively for the first time in the field of conservation science. The environmental survey allowed for detecting deterioration causes to the paint layer, such as humidity fluctuation, soluble salts and solar radiation (photo-induced alteration). Furthermore, dust and wind erosion, animals and unauthorized access to the sites were among the identified risks and damaging factors to the wall paintings. Local conservators and conservation scientists from the Department of Antiquities of Jordan (DoA) and the Petra Archaeological Park (PAP) were involved in various measures and a training on modern analytical methods has been offered to them.
Publications
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"Painting with gold in Nabataean Petra: Microanalysis, micromorphology and some conservation aspects", ICHAJ 14th Conference, Florence, Italy
Naes, Maram; Kanngießer, Birgit
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"Technical and provenance study of recently discovered Nabataean Marble Sculpture from Umm al-Biyara in Petra, Jordan", 10th International Round Table on Polychromy in Ancient Sculpture and Architecture, Berlin, 11.-13.11.2020
Naes, Maram; Agoridou, Polytimi; Mantouvalou, Ioanna; Förste, Frank; Schmid, Stephan; Kanngießer, Birgit
