The UCLA/Getty Program is pleased to welcome visiting scholar Dr. Xiaoqi Wang for the 2013-14 academic year. Dr. Wang received her Ph.D. at the University of Science and Technology of China in conservation science and archaeometry (2005). Her dissertation research focused on the conservation of ancient shipwrecks and waterlogged materials with work undertaken in the conservation lab of the Romano-Germanic Central Museum, Mainz, Germany. Xiaoqi was a postdoctoral fellow (2006-2012) at Nanjing University in geophysics performing archaeometric research on Chinese archaeological glass beads and pigments dating between 220B.C.-600A.D. She serves as the Research Fellow in Department of Archaeology at Nanjing University, where she has also been teaching archaeology undergraduate and graduate students about archaeometry and conservation science since 2005. She was a visiting scholar at the University of Vienna, Austria (2001) and the Romano-Germanic Central Museum (2004-2005), made possible with funding from the University of Vienna and Romano-Germanic Central Museum respectively
During her time here, Dr. Wang will be working with UCLA/Getty Program chair Dr. Ioanna Kakoulli, as well as other colleagues in the UCLA/Getty Conservation Program and the Cotsen Institute of Archaeology. She will continue her research on beads and pigments focusing on the use of LA-ICP-MS, lead isotopic analysis and microscopy for their analysis. She is also focusing on ancient Chinese scroll paintings and hopes to connect with conservators, scientists and scholars on the identification of deterioration issues and solutions for preserving the paintings.
In the fall of 2009, the UCLA/Getty Conservation Program offered the course “Introduction to Archaeological Materials Science: Scientific Techniques, Methodologies and Interpretation” (CAEM M210) that focused on basic scientific techniques employed for the examination of archaeological and cultural artifacts to answer questions of anthropological significance and their state of preservation. Among the techniques covered were UV/VIS/NIR spectrophotometry, X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM-EDS), and Fourier Transform Infrared Spectroscopy (FTIR). Students were assigned small research projects in which they would apply these techniques, in addition to others discussed in this and other courses, to the investigation of various materials to answer questions about technology and condition.
The four groups of artifacts studied were:
samples of a Byzantine wall painting from St. Neophytos, Cyprus
A series of 5 blue and 5 red pigment samples from the Enkleistra of St. Neophytos, the place of reclusion, in Paphos, Cyprus were analyzed to determine the pigments identity and possible alteration products. Fourier Transform Infrared Spectroscopy (FTIR), Variable Pressure Scanning Electron Microscopy – Energy Dispersive X-ray Spectroscopy (VPSEM-EDS), Polarized Light Microscope (PLM), and Binocular (stereo) Microscope (BM) were used to analyze the samples and due to the limitations of the techniques, only inconclusive assignments can be made on the pigments’ identity.
From elemental analysis it is suspected that the blue pigment is lapis lazuli and that there are two different red pigments which are cinnabar HgS and red lead (Pb3O4). However, without phase analysis of these samples, a positive identification cannot be made. Alteration of red to black and dark blue to light blue were observed for the samples analyzed. A possible alteration of Cinnabar is to metacinnabar. Documented alteration products of red lead are to plattnerite [β-PbO2] and anglesite [PbSO4]. Fading of lapis lazuli has been attributed to the breakdown of the Al-O-Si in the literature. However, it was not possible to verify if these are the alteration products with the available tools.
Fiber samples from a formative period mummy bundle from Tarapaca 40 in the Atacama desert of Chile were examined in an attempt to identify
them. Standards of human hair and alpaca were used for comparison. Fourier transform infrared spectroscopy (FT-IR) spectra were collected on the samples and standards. The morphology of the fibers and standards were examined using polarized light microscopy (PLM), scale casts and cross-sections. The spectra from the FT-IR analysis could not be used to differentiation between human and alpaca hair. Based on morphology, three samples were identified as camelid and two were tentatively identified as human.
The Fowler Museum at UCLA houses a collection of Japanese polychrome wooden masks. A pair of these masks, identified as “honomen” (gift or dedication mask), was attributed to the same maker based on their stylistic similarities. The museum records stated that the masks were dated to the 18-19th century and made in the style found in the Kyūshū region of Japan. However, neither the pairing nor provenance of the masks was supported by any textual or technical evidence.
The poster presented here summarizes the preliminary results from a comparative technical investigation on the Fowler masks, as a part of the research to answer the questions regarding the masks’ provenance and their paired attribution. Analytical techniques such as wood characterization, polarized light microscopy (PLM), x-ray fluorescence spectroscopy (XRF), x ray diffraction (XRD), gas chromatography-mass spectrometry (GC-MS), pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and micro-chemical analysis using environmental scanning electron microscopy (ESEM-EDX) were used to determine the masks’ material composition and methods of manufacture. The analytical results, combined with studies on the masks’ context of use and iconographic origins, provided material evidence that the masks were manufactured in close association with one another, although there was no firm evidence to establish that they were indeed manufactured by the same hand. Furthermore, identifying vitreous pigments on one of the masks pushed the mask’s estimated date of manufacture to 19th-20th century. This finding also added knowledge to a class of pigment not widely used in the Japanese palette until modern times.
Built upon the analytical understanding of the Fowler masks’ material composition and present condition, the research project concluded with a conservation treatment to improve the long-term stability of the polychrome. The most urgent treatment priorities were stabilizing the fragile matte paint surface and locally reinforcing the structural defects on the masks. Due to time constraints, consolidation of the paint was performed only on the red mask. Major structural defects on both masks were reinforced by filling the cavities in the wood with a light-weight and mechanically-reversible fill made of rolled-up Japanese paper, capped with a light-weight putty made from Acryloid B-72 bulked with glass microballoons for a better seal. The fill was then inpainted with Liquitex acrylic emulsion paint to reduce the color contrast between the fill and the wood.