|Vol. 17, No. 6||Oct. 9, 1997|
Chandra Reedy is a detective who unravels mysteries of the past, all the while keeping a watchful eye on the technology of the future.
Using a combination of modern methods and time-honored investigative techniques, the world-renowned art conservation scientist most recently was able to uncover a probable region of origin for more than 300 bronze sculptures made near the Himalayan Mountains in the medieval period.
The result of her work is a new book, Himalayan Bronzes: Technology, Style and Choices, recently published by the University of Delaware Press.
The book is a complete study of 340 medieval-period copper alloy sculptures from the Himalayan regions of Afghanistan, northern Pakistan, Kashmir, Himachal Pradesh, Nepal and Tibet.
Identifying the sculptures' origins was no small task, considering artists in isolated valleys adjacent to the mountains created the statues for more than 1,500 years to honor the deities of the Hindu, Buddhist and Bon-Pö religions.
Reedy is associate professor of art conservation and museum studies at the University of Delaware and director of its doctoral program in art conservation-the first doctoral program of its kind in the country. She uses a multidisciplinary approach to uncover ancient mysteries.
"I do think of myself as a detective," Reedy, who heads up the University of Delaware's new Laboratory for the Analysis of Cultural Materials, said. "I have to figure out who made an object, when they made it, how they made it and why. You have to follow lots of lines of evidence."
Following many paths is part of what makes Reedy's approach and her book different. Art historians traditionally classify, date and identify the regional origins of statues on the basis of artistic choices that are visible to the eye.
Reedy expands the idea of "visible" to include features that are only detectable under a microscope, with the aid of X-radiographs, and with analytical instruments.
"Object analysis is truly an interdisciplinary field. You need chemistry, geology and art history, plus anthropology and other fields," she said.
"In studying bronze sculptures of the Himalayas, first I look at any kind of documents available, say Tibetan or Sanskrit texts, to find out who was doing casting and where. I've been to Nepal and northern India to try and compare their different casting techniques. Also, I look at locations of copper ore, to find the sources."
When looking at a specific statue, Reedy said, "The first thing I do is look at the casting and decorative work on an object. I just eyeball it. Then, I do a microscopic exam to see worn surfaces and inlays. You also can do x-ray radiographs (similar to medical x-rays but stronger) to see if it is hollow or solid metal, and whether it has an armature. I then drill a hole, a very tiny one, and take a sample where I know I'll find the core.
"We're talking about a really tiny little drill bit, no larger than 1 mm. I cover the hole with wax and you can't see it," she said.
The metal sample is then dissolved and analyzed to determine which alloys were used and to match that with geographic locations of copper deposits.
Whenever possible, core material is extracted from statues that have been cast around a clay core. "We use dental tools to poke the clay out," Reedy explained.
"You take a little bit of a sample, about 15 milligrams, and smear it on a slide. Under the microscope, you can see the coarseness of the clay. They added a lot of sand and dung, carbonized plant materials and more to make the material more porous for release of gases so that when you're casting you don't get many flaws. Under the microscope, a sample looks like a kaleidoscope of green, gray, brown and white-depending on the mineral make-up. Chlorite, for example, is green; quartz is gray."
After recording all types of data, Reedy does a multivariate statistical analysis, in which all minerals are coded and put on computer to determine their values. She uses software designed for biomed applications and always works with a statistician.
"After the statistical analysis, I go back to the original historical art analysis. It's not a black box-it doesn't give you answers immediately and there can be more than one way to review the results. You have to make sure they make sense.
"I start with several hypotheses about something. Sometimes I can reject some possibilities after the microscopic exams, sometimes I can't. It's ambiguous," she said.
Reedy began her materials analysis of artifacts while a student in the archaeology program at the University of California at Los Angeles, where she worked with neutron activation analysis.
"Under a microscope, you measure the optical properties of elements by looking at them through plane polarized light and cross polarized light," she explained. "With neutron analysis, you look at rare Earth elements and trace elements, things like sodium. Clay deposits have characteristic patterns and ratios of elements, which is like a signature."
Other researchers in the art conservation program who work in other media, such as glass where they can't use an invasive technique, can use the University's proton-induced X-ray emission spectrometer, known as PIXE. One of only three such machines in the world available for work on art objects (one is in the Louvre), the huge Vandergraf accelerator sends a beam of protons onto a spot on the sample. It temporarily knocks the electrons out of their orbits, and, as they go back, they emit secondary X-rays that are characteristic for each element. Reedy has used this process on early American glass with Charles Swann, professor emeritus at the Bartol Research Institute at UD.
The implications for art conservation go far beyond the immediate field, Reedy said. "We're not just working with fine art objects. We're working with a craft, with what people left behind. By doing scientific analysis in conjunction with historical work, we can get a fuller sense of how people used these objects in their everyday lives.
"I'm interested not only in fine art but in material culture," she said. "We have all kinds of materials in our home, and some will be left behind for scientists to study in the future. It will tell them something about us."
Reedy, a member of the UD faculty since 1989, received her doctorate at the University of California at Los Angeles.
-Ginger Pinholster and Beth Thomas