Our students and faculty are getting ready to head east to attend the 2015 ANAGPIC conference this week. This year, the conference will be co-hosted by the Winterthur/University of Delaware Program in Art Conservation (WUDPAC) and the University of Pennsylvania’s graduate program in Historic Preservation. This is the first time that UPenn will be hosting ANAGPIC. They, along with Columbia University’s Historic Preservation program, joined ANAGPIC a couple of years ago. The addition of these programs broadens the scope of the papers presented and provides additional opportunities for students and preservation professionals to share information about their recent research and projects.
The UCLA/Getty Program will be well represented with 2 speakers and 4 posters. Abstracts of our program’s presentations are found below. For a full list of papers/posters presented and more information on the conference, you can check out the ANAGPIC 2015 website. And make sure to check out our Facebook page and blog for photos from the conference.
Torqua Cave: Documentation and Condition Assessment of Catalina’s Rock Images
The site of Torqua Cave is a rock shelter on Catalina Island, located 20 miles off the coast of Southern California. The largest of the Channel Islands, Catalina has a fascinating geologic history and is rich in marine and lithic resources. It was was inhabited at least 9000 years BP by the people known today as the Island Tongva. The first documentation of Torqua occurred in the early 1970’s with the identification of 19 red pictographs, although by today’s standards this campaign was not sufficiently systematic. To date there is little to no characterization of the site’s physical history.
This paper presents the results of new imaging technologies based on Decorrelation Stretch and an assessment of local climatic conditions and substrate composition, which will lead to a better understanding of the site’s history and deterioration. Following an assessment of condition, the significance of the site to its stakeholders, including the indigenous population, the island’s contemporary residents and its landowners, will be investigated.
Decorrelation Stretch is a method of producing false color digital images that is able to reveal severely faded pigmented decorative surfaces, which has been used successfully here to identify previously unrecognizable and invisible pictographs. Photogrammetry will be performed to create a unified image of the site, which, at roughly 50’ long and on a hillside, has not been possible to present previously. X-Ray Diffraction has identified the pigment used and the composition of its substrate. Portable x-Ray fluorescence (XRF) spectroscopy and ultraviolet/visible/near infrared (UV/Vis/NIR) reflectance spectroscopy will be performed on-site to create a map of the panels’ surface composition for comparison with visual characteristics such as color variation, patterns of deterioration, presence of water from various sources, and accretions. Polarized light microscopy (PLM) will be performed on a thin-section slide of the host rock’s substrate for identification of its composite minerals. Environmental data loggers will be placed at the site to measure ambient temperature (T) and relative humidity (RH) at the site through daytime/nighttime cycles for a year to compliment spot measurements of rock surface temperature, T and RH that were collected in summer 2014.
This information will be used to characterize the degradation patterns of the bedrock panels that comprise this site, focusing on the interrelationship of the rock’s composition, local climate and water transfer through the rock and from external sources. An assessment of the site’s significant and the danger of anthropogenic impact will lead to recommendations concerning future management strategies and protection.
An Analysis of Unidentified Dark Materials Between Inlaid Motifs on Andean Wooden Queros: Preliminary Findings
Paramount in the study of Andean civilizations, past and present, are the people’s rituals and ceremonial customs which have pervaded the Inka and post-Inka periods. These rituals mark social and religious occasions with offerings to the gods that ensure economic prosperity and good health. Decorated wooden cups, called qeros, have facilitated these customs through the centuries, witnessing long use-lives as they are passed down from generation to generation. As custodians of ancient Andean rituals and ways of life, contemporary Andeans use the cups as their ancestors did: to hold and transfer libations of blood or the fermented maize beer chicha, to honor, respect, and celebrate religious, social, and economic activities. It is from here that qeros enter museum collections, their use-life ends, and their preservation as vestiges of Andean culture and ritual begins. In recent years there have been technical studies of Andean qero technology focusing on the materials used for the polychrome inlay decoration, identified as an array of natural and manufactured pigments bound by an organic resin from species of the Elagaeia tree (E. utilis and E. pastoensis), locally known as mopa mopa. However, currently there is a lack of information concerning the dark material(s) present around the polychromy, which exhibits peculiar and substantial loss on vessels in many museum collections, sometimes as though it has been physically scraped off. For this study, different dark materials surrounding the polychrome design on a group of qeros belonging to the Fowler Museum at the University of California-Los Angeles were investigated in an effort to characterize them and potentially explain the technical, cultural, and/or ethnographic reasons for their presence and causes for their loss. Various documentation and analytical techniques were employed, including visual analysis, digital photography, UV-induced visible fluorescence, Reflectance Transformation Imaging (RTI), microscopy, portable X-Ray Fluorescence (pXRF) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and Gas Chromatography-Mass Spectrometry (GC-MS). Preliminary results have shown surface modification and ethnographic wear which appear related to the material’s loss. Identifying this material(s), understanding its origin and explaining its loss will contribute to our knowledge of the vessels’ manufacture and/or ethnographic history and use, and guide our transferred custodianship over such artifacts of Andean traditions.
Technical study of a miniature Tuareg camel saddle using X-radiography and X-ray fluorescence spectroscopy
Elizabeth Anne Burr
A miniature camel saddle from the Fowler Museum is an example of the dyed leather and metal work for which the Tuareg of Niger are known. This saddle made by Hamidan Oumba for the tourist market is a replica of traditional tamzak camel saddles used by the Tuareg elite. It was suggested by an African art scholar that a miniatures such as this would be constructed using the same materials and techniques as a traditional tamzak with a wooden frame. However, X-ray imaging revealed a substrate that included more dense materials in addition to wood. X-ray fluorescence spectroscopy (XRF) data was acquired from a number of locations over different substrate materials (as corresponding to x-ray images), and different types of dyed leather, which were overlaid for interpretation. Correlations were found between the dense substrate material and the trace elements rubidium and strontium used to identify clays. This and the texture seen in X-ray image suggest that clay based components of the frame were manufactures for this object, a deviation from a traditional construction. Also, the turquoise leather was found to be rich in chlorine, copper, and tin, suggesting the use of bronze chloride corrosion to create the leather pigmentation as is traditional among the Tuareg. These results suggest a combination of both innovation and tradition in the construction of this art piece.
Diagnostic Imaging Techniques for the Identification of Tortoise Shell
The focus of this poster is the documentation of a specific patterning, found within and unique to tortoise shell, made up of random swirling lines, which most likely correspond to the yearly depositions of keratin that occur as the turtle grows. This phenomenon has been observed in passing in some literature, but has not been fully characterized and is little understood in any discipline. The patterning has been observed as topography in some antique tortoise shell samples, and also as darkened lines in an example that appears to have suffered light damage. This poster will illustrate how documentation techniques including UV-induced visible fluorescence and Reflectance Transformation Imaging (RTI) have proven to be extremely useful in observing and documenting the pattern, and how characterization and further understanding of the pattern can be used as a diagnostic criteria for distinguishing tortoise shell from imitative materials such as plastic and horn.
The documentation illustrated in this poster is one component of my master’s thesis research about light-induced alterations to tortoise shell, and specifically how light may induce alterations to the patterning described, such as darkening and increased visibility. For the study, two taxidermied hawksbill turtles (Iretmochelys imbracata) were generously donated by the US Fish and Wildlife Department of Forensics, and the scutes from one turtle carapace were removed for use as the sample material. The samples are currently undergoing accelerated light aging under three different parameters: exposures mimicking window lighting (which filters some UV), museum lighting (which filters nearly all UV) and a chamber emitting UVA radiation. An important outcome of this research will be a better understanding of photochemically induced alterations in tortoise shell, and preventive lighting guidelines for tortoise shell materials based on the findings of the light aging study.
Piecing together the history of an 18th century printed Armenian Prayer Scroll
The use of prayer scrolls along with other religious art and literature have for played a significant role in the Armenian culture since the 5th century. The scope of this study is to investigate the history and materials used on a printed, 18th century Armenian prayer scroll. This analysis involves the examination of the scroll with the use of non-destructive analytical photography, fiber optic ultraviolet-visible and near infrared reflectance spectroscopy, X-ray fluorescence and Raman spectromicroscopy. The study attempts to identify and characterize pigments, colorants, ink, and the paper used to construct the prayer scroll. The text along with the illustrations have been translated and studied in an attempt to provide an overall understanding of the scroll, printing techniques, religious significance, use, as well as the traditional practices in the Armenian culture in the 18th century.
Preliminary Research on Biocorrosion of Archaeological Glass
The scope of this research is to investigate the mechanisms and process of biologically induced corrosion of archaeological glass. Archaeological glass samples from Greece and Cyprus suspected to have undergone biocorrosion were analyzed to characterize the chemical composition, microstructure, and topography to determine the difference in the chemistry of the glass surface and the bulk. Analytical techniques included scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray fluorescence (XRF) spectroscopy. Modern glass samples were placed in petri dishes with sulfuric and oxalic acid to simulate potential corrosion from acids produced by microorganisms. This research aims to fill a gap in our knowledge on glass biocorrosion and to evaluate the effects of microorganism on archaeological glass.