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Volume 87 Issue 42 | pp. 12-16
Issue Date: October 19, 2009

Cover Stories

Science From Art

Chemists tap museum collections as a rich source of novel research questions, collaborations
Department: Science & Technology
Keywords: art conservation, cultural heritage science
[+]Enlarge
TRUE COLORS
X-ray fluorescence spectroscopy is used by MMA scientists to investigate the original polychromy of a Roman sculpture.
Credit: Metropolitan Museum of Art
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TRUE COLORS
X-ray fluorescence spectroscopy is used by MMA scientists to investigate the original polychromy of a Roman sculpture.
Credit: Metropolitan Museum of Art

For some chemists, the next research project may be a collaboration with scientists at the local art museum. Increasingly, staff scientists at museums across the U.S. have been reaching out to colleagues in academe to pursue novel research questions about the art and cultural heritage objects housed and cared for at their institutions.

Now, in a watershed event, the National Science Foundation, through its Chemistry Division, plans to issue its first solicitation to specifically fund research of this kind. This new funding coupled with existing funding from private sources have many associated with the field excited about the potential research opportunities that might emerge.

Scientific research on art museum collections has been going on since at least the 1930s. But especially over the past 30 years, many museums have been adding scientists to their ranks in order to better understand and preserve the artistic and cultural heritage objects under their care. These scientists—many of them chemists—comprise the field of conservation science, which some people now refer to as cultural heritage science. It includes studies of archaeological objects, cultural heritage properties, fine arts collections, archives, historical buildings, monuments, and so on.

For instance, the J. Paul Getty Trust supports one of the largest science operations at a museum complex in the U.S. The Los Angeles-based institution includes support for interns, postdoctoral fellows, and visiting scholars. It also houses the Getty Conservation Institute (GCI), which serves the conservation community through scientific research, education and training, model field projects, and the dissemination of the results of both its own work and the work of others in the field.

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CLOSER LOOK
Trentelman uses a Raman microscope to study which pigments were used in one of the illustrations in Martín de Murúa’s “Historia general del Piru.”
Credit: © J. Paul Getty Trust
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CLOSER LOOK
Trentelman uses a Raman microscope to study which pigments were used in one of the illustrations in Martín de Murúa’s “Historia general del Piru.”
Credit: © J. Paul Getty Trust

Current research projects at GCI include one that seeks to reduce the damage to works of art on paper caused by museum lighting and another at the Herculaneum archaeological site in Italy that includes site-specific scientific analysis. The aim of another project is to enhance knowledge of the fundamental properties and performance of high-calcium lime mortars and plasters to provide a wider basis for the appropriate choice of materials and methods in the conservation of this widely used building material.

The new NSF solicitation is designed to bring in more academic researchers to contribute to such projects. According to NSF Chemistry Division Program Officer Zeev Rosenzweig, “The solicitation calls for collaborative proposals involving chemists or materials scientists from museums and academia to address grand challenges in the area of science for cultural heritage.

“At first, the proposals will be limited to chemistry and materials issues related to cultural heritage science,” Rosenzweig says. “These include but are not limited to dynamic studies of material degradation (experiment and theory), the development of new protective materials (coatings) suitable for artwork, understanding the impact of environmental parameters on the surface chemistry of artwork, and the development of new analytical methods and quantitative imaging techniques for noninvasive, nondestructive analysis of artwork.”

In terms of funding, “we are looking for a modest start of $3 million to $5 million in funding for fiscal 2010,” Rosenzweig continues. “The exact level of funding will depend on the quality of projects. We will solicit three-year projects and hope to further increase the investment and the number of funded projects over the years.”

More On This Topic

Interested in a career as a museum scientist? Read about Getty Conservation Institute scientist 
Catherine M. Schmidt’s journey.

Leading up to the solicitation, NSF and the Andrew W. Mellon Foundation sponsored a workshop this past summer entitled “Chemistry and Materials Research at the Interface between Science and Art.” It was meant to identify the grand challenges in the field as well as increase awareness of the research opportunities available at art museums.

Many people who work in cultural heritage science say it is important to note that, while research opportunities are numerous, it is a field with limited job opportunities. Many chemists who work in the field today have come upon it in the course of pursuing otherwise typical graduate and postgraduate training in chemistry or chemistry-related disciplines. Others have maintained a long-term interest in art and art history and have sought out opportunities to work in museums. The important point, they say, is that scientific work on art objects can help make the science accessible to students and the public. Moreover, the techniques used to analyze works of art or artists’ materials can apply broadly.

According to a project summary for the NSF/Mellon workshop: “Cultural heritage, as the material evidence of humankind’s accomplishments, is a rich repository of basic scientific questions. A quantum leap in our understanding of cultural heritage, its materials issues and its conservation, is possible by fostering partnerships between scientists in cultural heritage institutions and those in universities and national 
laboratories.”

There are three grand challenges for cultural heritage science, says Richard P. Van Duyne, a professor of chemistry at Northwestern University who has conducted collaborative research projects with staff scientists at the Art Institute of Chicago. The first challenge, he says, is to develop advanced analytical techniques or tools—“something like MRI (magnetic resonance imaging) for biology.” By that he means tools that are noninvasive and nondestructive but able to yield significant information about the artwork or object in question. The idea, he says, is to “do nothing but learn everything.”

Right now, Van Duyne continues, one of the primary noninvasive methods for analyzing paintings is infrared photography. This technique allows penetration of the painting layers to reveal an underdrawing, or preparatory sketch for a painting. Additionally, X-ray radiography allows researchers to penetrate the uppermost painting layers and, exploiting the different densities of the paints—based on the presence or absence of heavy-metal components, especially lead—bring to light compositional changes or paintings underneath paintings. But these techniques can’t identify the organic or inorganic components of the pigments in the paint or determine if any biological materials are present.

To get molecular information about the paint on a painting, Van Duyne says, researchers can turn to technologies such as Raman spectroscopy or surface-enhanced Raman spectroscopy (SERS). Recently, Van Duyne and chemist Francesca Casadio of the Art Institute of Chicago and coworkers used SERS to analyze pigments in a variety of media, including six pastel sticks that belonged to the artist Mary Cassatt and a pastel artwork by Cassatt (<em>Anal. Chem. </em> 2009, <em>81, </em> 7443; C&EN, Aug. 10, page 31).

Another challenge, Van Duyne says, is to better understand material degradation. “If you’re going to restore an object, you need to know how it has changed over time,” he says. For works of art and other objects, that can mean understanding how materials degrade over hundreds and sometimes thousands of years.

To understand material degradation processes, researchers often must turn to laboratory simulations to replicate those processes, says Paul Whitmore, professor of chemistry and director of the Art Conservation Research Center at Carnegie Mellon University, in Pittsburgh. For example, he says, replicating burial environments can reveal degradation processes that have affected a cultural heritage object. “We can make predictions from the simulations and compare with the cultural object,” he says.

The degradation of modern artworks is “one of the big issues in the conservation field at the moment,” says Thomas J. S. Learner, senior scientist at GCI. GCI, he says, has three main projects in this area: modern paints, murals and outdoor sculptures, and plastics. Each project seeks to understand the materials used by artists; what happens to them over time on display or in storage and how best to stabilize, clean, and restore the objects.

The third grand challenge for cultural heritage science builds on the second, Van Duyne says, and that is developing new methods for material stabilization, strengthening, and repair. Conservators have many tools available to stabilize and protect works of art. Objects may be cleaned with solvents, detergents, or enzymes. Structural repairs can be done with a variety of adhesives and reinforcement materials. Appearance of deteriorated surfaces can be improved with stable retouching paints to disguise damage and patching materials to fill areas of loss. But basic research could contribute still more options, he says.

“We need to understand the effects of treatments and design new ones,” says Barbara H. Berrie, a chemist and senior conservation scientist at the National Gallery of Art, in Washington, D.C. “The use of materials cannot result in any change of appearance to a work of art—a severe limitation.

“Inside works of art, there are these nanostructures; for example, nanoparticles of silver in stained glass,” she explains. “We must understand these structures to treat and conserve art objects. We have big issues in terms of stabilization.”

Twenty years ago, Berrie continues, people were putting films and coatings on works of art, “but they can cause more damage. We need to understand more about the energy of surfaces to understand how these treatments will interact. Perhaps we need to think about paint as a metal organic framework—it gives us a way to think about a work of art as a chemical system. These are things that we can probe and understand.”

[+]Enlarge
FULL PICTURE
Scientists at MMA used surface-enhanced resonance 
Raman scattering to analyze a leather quiver fragment (top left) from ancient Egypt (ca. 2124–1981 B.C.) to generate a polarized reflected light photograph of a sample removed from the red painted area of the quiver (bottom left), and the SERS spectrum (solid line). The dashed line is the spectrum of a 2nd-century B.C. pink pigment from Corinth, Greece.
Credit: Proc. Natl. Acad. Sci. USA
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FULL PICTURE
Scientists at MMA used surface-enhanced resonance 
Raman scattering to analyze a leather quiver fragment (top left) from ancient Egypt (ca. 2124–1981 B.C.) to generate a polarized reflected light photograph of a sample removed from the red painted area of the quiver (bottom left), and the SERS spectrum (solid line). The dashed line is the spectrum of a 2nd-century B.C. pink pigment from Corinth, Greece.
Credit: Proc. Natl. Acad. Sci. USA

With its decision to fund research in conservation science, NSF joins museums themselves and the Mellon Foundation in supporting such research in the U.S. In fact, many people who work in conservation science credit the efforts of Mellon Foundation Program Officer Angelica Zander Rudenstine with keeping the field alive over the past 10 years.

Thanks to Rudenstine, an art historian, the foundation has, since 2001, poured more than $43 million into cultural heritage science largely by funding endowed positions for scientists at museums and training programs and by establishing postdoctoral fellowships in cultural heritage institutions. But, Rudenstine says, “there is no way Mellon can continue to invest at this level, or on its own. A lot of what we have done is to sow seeds.”

Rudenstine, in turn, credits NSF’s Rosenzweig and some of his colleagues with recognizing the merits of cultural heritage science for government funding of the research.

“We believe that the field of science for cultural heritage can benefit from increasing involvement of chemists and materials scientists from academia since it poses fundamental challenges that are not very different from those faced in other areas supported by NSF,” Rosenzweig says.

“For example,” he continues, “the challenge of understanding the dynamic properties of complex systems, in this case cultural heritage artifacts, and the need to develop new sensitive and nondestructive analytical techniques to interrogate these precious samples are not unique to the field of cultural heritage science. The tools and understanding developed promise broad impact both within and beyond the cultural heritage community. The field of science of cultural heritage also offers an excellent opportunity to illustrate in terms the general public can understand and appreciate the practical impact of fundamental research.”

In the past, some officials at NSF “were not getting it,” Rudenstine says. She and many others perceived a prevailing attitude that conservation science is applied science and not fundamental research. “The peer review committees would say, ‘It’s not really science,’ and then refer us to the National Endowment for the Humanities.”

Rosenzweig responds to this applied versus basic research question by noting that “some aspects of the field of science of cultural heritage are applied in nature and indeed not appropriate to NSF. In the solicitation, NSF focuses on fundamental aspects of the field. NSF has supported fundamental projects in the field over the years, but it has been anecdotal. The solicitation is an attempt to build a more significant award portfolio in order to address the grand challenges in the field.”

The NSF funding opportunity may also increase the number of scientists working in this area. Currently, only a handful of museums around the country have research scientists on staff. At the Metropolitan Museum of Art (MMA), in New York City, chemist Marco Leona heads up the Department of Scientific Research, which has 10 scientists on staff who work in a variety of laboratories, including an organic chemistry lab.

Leona says that about 70% of the research by museum scientists is service related—that is, the result of some request for information by art historians who might be trying to authenticate a particular work of art, for instance, or conservators who are trying to preserve or restore works of art. “The word ‘routine’ doesn’t exist here,” he says.

Because of the varied nature of the museum’s work, it is often necessary to make extensive use of collaborations, Leona explains. “We identify a problem and bring in the relevant person.”

For example, Leona has worked with John R. Lombardi, a chemistry professor at the City College of New York (CCNY), on a variety of projects. They have used SERS to identify natural dyes in ancient and historical textiles (J. Raman Spectrosc. 2007, 38, 853) and Raman spectroscopy and SERS to analyze synthetic dyes found in ballpoint pen inks (J. Forensic. Sci. 2009, 54, 947). Most recently, Leona reported on the use of SERS to identify natural organic colorants in archaeological objects, polychrome sculptures, and paintings from samples smaller than 25 μm in diameter ( Proc. Natl. Acad. Sci. USA 2009, 106, 14757).

“It was fascinating to see how we could apply science to art,” says Charles Corredor, who as an undergraduate student worked with Lombardi and Leona on a project using SERS to identify pigments in different textiles from MMA’s sample database. Corredor learned about the collaboration while taking a physical-chemistry class with Lombardi. He says the experience, which led to a pair of publications, and the contacts he made, especially with Leona, have helped him move on to graduate studies in chemical engineering at CCNY.

The undergraduate research experience, he says, was a remarkable opportunity given to him by Lombardi and Leona. Corredor points to unexpected results from his undergraduate work: three international research projects in China, Sweden, and France and an invitation to a Junior Research Scientist Conference in Austria, where he presented his results and data. “Thanks to [Lombardi and Leona] I was able to have a better understanding of science and reconfirm my devotion to it.”

At the Art Institute of Chicago, Casadio is the museum’s senior scientist, and she helped tailor a collaboration with Northwestern University. The program was initially funded by the Mellon Foundation to the tune of $500,000 and set to run for three years, but, due to its success, it has recently been approved to continue beyond this window.

The program consists of collaborative research, education, and seminars carried out with the university’s departments of materials science and engineering, chemistry, and computer science. Professors, postdoctoral fellows, and graduate and undergraduate students have been involved in projects that include technical studies of Asian art materials, scientific studies of modern artists’ materials, and studies of artistic metals, from archaeological to modern.

“I didn’t think when we started out that we could achieve so much,” Casadio says. She says the program has resulted in 15 publications, eight symposia, and widespread media coverage of the program.

From a training perspective, Northwestern professor of materials science and engineering Katherine T. Faber says she is not worried about involving students in research projects for a field with limited job opportunities. “We teach students to solve problems,” she says. “The techniques work as well on a 3,000-year-old archaeological object as they do the next aerospace alloy.”

Research on works of art does seem to be of inherent interest to students and the general public, says Karen Trentelman, senior scientist at GCI. She recalls, for instance, work on a nearly 400-year-old Peruvian manuscript that was exhibited at the J. Paul Getty Museum in 2008. The work of a 17th-century Spanish friar, Martin de Murúa, the manuscript documents the history of Peru through a presentation of the Inca kings and queens. In addition to the Getty’s Murúa, only two other illustrated histories of Peru written during this era are known to exist.

Trentelman used X-ray fluorescence and Raman spectroscopy to identify the pigments used in the manuscript illustrations. A broader question was how well illustrations in the manuscript actually matched Peruvian textiles of the same time period. She says visitors to the exhibition and attendees at accompanying symposia were fascinated by the scientific work and how it could inform art historical questions. “I had Raman spectra right there in the exhibition gallery,” she notes.

Other scientific research at the Getty by Trentelman and her colleagues includes use of Raman spectroscopy to investigate the painting materials and techniques of the late-15th-century manuscript illuminator Jean Bourdichon (J. Raman Spectrosc., DOI: 10.1002/jrs.2186); the use of scanning electron microscopy to characterize samples of red and black gloss from Greek Attic pottery of the late 6th to 5th centuries B.C. ( Archaeometry, DOI: 10.1111/j.1475-4754.2008.00413.x); and elemental analysis by inductively coupled plasma time-of-flight mass spectrometry of seven Roman-period Egyptian mummies (Archaeometry, DOI: 10.1111/j.1475-4754.2008.00440.x).

While large museums like MMA, the Art Institute of Chicago, the National Gallery of Art, the Getty, and the Smithsonian Institution have considerable scientific expertise at their disposal, many other, smaller museums do not. “Museums tend to go after scientific expertise when it’s needed, but it’s not always the right expertise,” Carnegie Mellon’s Whitmore says. To bridge the gap, he says, “it’s critical to have scientists heavily engaged in studying cultural heritage objects.”

 
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