Oberlin Alum Gives Talk on Chemical Detective Work
April 22, 2011
This past Wednesday, the College welcomed back one of its esteemed alumnae for a talk on the interdisciplinary nature of art history and art conservation. Claire Barry, OC ’77, came as a part of the Blumeno Lecture Series, which aims to bring speakers to campus to lecture on the overlap of chemistry and art.
Barry is currently the director of conservation at the Kimbell Art Museum in Fort Worth, TX, and gave a lecture titled “Autoradiography and La Tour: Placing a 17th Century Masterpiece in a Nuclear Reactor and Other Adventures in Paintings Conservation.” In her seminar, Barry detailed how chemistry and various instruments of chemical analysis play an integral role in studying paintings that are hundreds of years old — both in determining whether or not an artist actually painted a piece which bears his name, and in gaining insight into the particular techniques employed in the artist’s creative process.
Barry became interested in conservation during her first year at Oberlin, when she spent a semester abroad in France interning in the conservation department of the Louvre Museum. “Something about connecting directly with the actual object just clicked with me,” remarked Barry.
Inspired by the work she did there, Barry returned to Oberlin to pursue a degree in Art History, specializing in art conservation. At the time, Oberlin College was home to an Art History Master’s program, as well as a graduate program for training art conservators.
“Oberlin was the perfect place to pursue [art conservation], with its Art History program, the art museum and a fabulous chemistry department,” said Barry of her alma mater. “I almost couldn’t have picked a better college for the field I ended up going into.”
Barry’s lecture focused on her work in three separate case studies: Fernando Gallego’s “Altarpiece for the Cathedral at Ciudad Rodrigo” Michelangelo’s “The Torment of St. Anthony” and Georges de La Tour’s “Cheat with the Ace of Clubs.”
A 26-panel piece from the 15th century, Gallego collaborated with fellow artist Maestro Bartolomé to complete the enormous altarpiece. In order to differentiate between the panels painted by Gallego and the panels painted by Bartolomé, Barry and her colleagues used an analytical technique known as infrared reflectography to reveal the underlying layers of the painting.
Infrared reflectography uses infrared light — light with a wavelength below a human’s visible range — to view what is known as an “underdrawing,” or the initial sketches made by the artist. Infrared cameras take pictures of small pieces of the original painting, and these pictures are then strung together to form the underdrawing version of the entire painting.
The underdrawings were typically painted with a water-based carbon substance by the artist before the painting was begun to serve as a guide, and can often provide information on an individual’s style and also on the way the painting evolved as it was created. Pentimenti — changes made by the original artist between the sketch and the final, painted version — are often visible through infrared reflectography. The reflectography of the panels done by the two artists indicated distinct differences in their style of underdrawing. Barry and her team of conservators had access to other pieces of Gallego’s work, which allowed them to determine which panels were his.
In May of 2009, the Kimbell Art Museum acquired what is thought be many experts to be Michelangelo’s first painting. The piece was therefore subject to great scrutiny by Kimbell’s experts, searching for evidence that it was indeed an authentic Michelangelo. As Barry commented, “When the Kimbell acquires a new painting, sometimes it takes a few years for people to agree [on if it is attributed to the correct artist].”
In this case, Barry and her fellow experts employed the technique of X-radiography, which bombards a section of the painting with X-rays. These X-rays are easily absorbed by white, lead-based paint, a common material in Michelangelo’s time. The technique allows conservators to detect any trace of more modern paints, like titanium-based white pigments, which were not available in the 15th century and would therefore indicate forgery. It also reveals places where the artist may have originally painted something; though a new layer of paint now covers what lies beneath, the X-radiography techniques are able to reveal places where Michelangelo had used white paint originally.
In the case of La Tour’s “Cheat with the Ace of Clubs,” Barry described a variety of analytical techniques employed to verify authenticity. It is known that La Tour often made copy prints of some of his more famous works — a fact that raised questions of authenticity since the Louvre and the Kimbell both own a “Cheat with the Ace of Clubs,” and neither was sure which was the original.
Though there is still some contention, it is believed by most experts that the Kimbell is the owner of the original work. The X-radiographs of the Kimbell’s version contain a large number of pentimenti, indicating that it was the original painting La Tour first worked on.
After describing her experiences working with these three paintings, Barry also spoke briefly on several recently-developed analytical techniques that are giving the art world new insight into the works it studies.
Autoradiography, for example, is a process by which the painting is first exposed to nuclear radiation and then film in increasing time increments over the course of a few days. This process allows historians to learn about a painting’s original color by the metal used in the paint. Because different metals decay at different times (or have different half-lives), each exposure — from 15 minutes to one day after exposure — looks different.
Many of the paints used before the modern era change color as they decay or are exposed to other elements. Autoradiography thus gives information on the original colors of many paintings. Barry told her audience that “museums are filled with Madonnas dressed in black cloaks that were originally red.”
Another technique known as “synchrotron radiation induced X-ray fluorescence spectroscopy” is able to analyze different layers of the painting — from the specific canvas used to the layers of paint that lie beneath the finished product. Historians believe that about one-third of Vincent Van Gogh’s paintings were created on canvases he had already painted once before. This new technology allows experts to uncover the truth behind these types of pieces, which, until now, has only been assumed.
Barry, who succeeded in melding the fields of chemistry and art in her career, stressed the importance of interdisciplinary overlap for Oberlin students and in education in general.