By Alberto Tagle

Private conservator Chris Stavroudis applying a gel-based cleaning system. Stavroudis was participating in a week-long experiment organized by the GCI that was a component of a larger Institute study of gels-based cleaning systems. Photo: Dusan Stulik.

The introduction of scientific methods and studies into the field of museum collections, monuments, and art had its first manifestations in the late 18th century with the work of German scientist Friedrich Klaproth, who analyzed the composition of metal coins. Klaproth was soon followed by others. For example, in the early 19th century, French chemist Jean-Antoine Chaptal published studies on Pompeian pigments, while British scientist Sir Humphry Davy published results from research on pigment materials in Roman archaeological finds. Others—like chemist Michael Faraday, who studied the effects of glass protection of paintings at London's National Gallery, and German metallurgist Ernst von Bibra, who wrote a compendium of metal analysis based on a study of museum collections—increased the body of work in the field.

The aspirations of these scientists included a better understanding of materials, an enhanced knowledge of historical and ancient technologies in art, an improved ability to attribute objects to historical periods and groups, and the authentication of objects. Their efforts were part of the general European embrace of science—what Canadian conservator and anthropologist Miriam Clavir has described as "an optimistic belief in science as the key to progress for humankind, and an ensuing attribution of 'higher moral ground' to knowledge gained through science."

The first museum laboratory was established in 1888 by Friedrich Rathgen when he was appointed head of a new scientific institution, the Chemical Laboratory of the Royal Museums of Berlin. This facility's primary purpose was to contribute to the understanding of the deterioration of the collection's objects and to develop treatments to arrest that deterioration.

With this, conservation science was born.

Throughout the first half of the 20th century, new laboratories worked at designing treatments to improve restoration and conservation of objects. Initial efforts concentrated on answering analytical questions and questions about the original technology and the materials of objects and monuments. Extensive and fundamental studies were undertaken that created the basis of the present knowledge that helps us define and understand the material aspects of cultural objects.

During the second half of this century—in the wake of the immense damage to cultural heritage during World War II, as well as advances in chemistry and the development of synthetic materials—a more systematic and profound research effort was put into the design and elaboration of restoration techniques and conservation materials. Synthetic polymers and "modern" materials were introduced in restoration practice (sometimes in a manner that was relatively hasty compared to today's more cautious approach). The testing of numerous materials to slow deterioration greatly improved, and specific materials were synthesized and produced to address conservation needs.

In short, the scientific and technical revolution had come to influence the preservation of art and monuments.

Preventing Damage

Today, at the end of the 20th century, preventive conservation has made its entry into the field, influencing scientific research. A more critical, hands-off approach has evolved, based on a better understanding of conservation problems and of decay mechanisms of objects, as well as on knowledge of the failure of some modern materials that were introduced into the field. The question now is how to prevent damage—thereby limiting direct intervention on objects to the absolutely necessary. This approach promotes the design of conservation treatments that ensure, as best as possible, that no damage occurs.

Scientists at the GCI are pursuing this objective through the Institute's research projects. With a focus on the needs of practicing conservators and conservation scientists working to preserve objects, art, architecture, archaeological sites, and monuments under their care, the GCI's main scientific research goals reside in studies of deterioration phenomena and in the design and evaluation of conservation treatments that can provide a wide margin of security to objects and sites. The GCI also conducts research on materials' composition and early technologies that can contribute to the scholarly interpretation of art and artifacts from the past.

Among current projects at the GCI is a long-term study on the effect of salt crystallization on the deterioration of porous stone, a conservation problem for monuments around the world. The knowledge gained from this study—which is being done in conjunction with projects at Maya sites in Central America—can help lead to the design and evaluation of preventive and minimally invasive conservation methods that slow the decay of porous stone that results from the interaction of water and salts. Another GCI study related to the Maya project—one also with application to outdoor sites around the world—is an examination of the performance and the deterioration of lime-based mortars and plasters, the most common binding and surface components of decorations on walls found in archaeological and historical buildings. As with the porous stone study, understanding the properties of these mortars and plasters and how they deteriorate is critical to developing preservation methods.

In another area, the GCI is continuing research into detecting threats posed to collections by atmospheric pollutants. This work—which has been going on since the mid-1980s—has included the testing of passive sampling devices for the detection of indoor-generated gaseous air pollutants that cause serious damage to metal objects (especially lead); to calcareous materials such as seashells, limestone, and low-fired ceramics; and to collagen-based materials like parchment and leather. The GCI has recently been working with the University of Strathclyde in Glasgow, Scotland, and with the Netherlands Institute for Cultural Heritage in Amsterdam, testing sampling devices that can detect organic carbonyl pollutants (e.g., formaldehyde, formic acid, and acetic acid).

A set of passive monitors being placed in a display case at the Santa Barbara Museum of Art. The GCI has long been investigating ways to detect atmospheric pollutants that can threaten collections. Photo: Cecily Grzywacz.

The ultimate objective of GCI research is the design of conservation approaches that can slow the deterioration of materials and, at the same time, prevent further damage while fulfilling the first requirement for any introduced material or new intervention: compatibility. In proposing treatments and solutions, the Institute goal is to find and utilize materials compatible with the original substance of the treated object or monument. It is not enough that a treatment is "reversible"; substances used in treatments should be compatible with the original materials and not contribute to damage, either during contact or in subsequent removal.

For example, in using a polymer or resin for consolidation or for joining parts of an object, it is not the strongest, hardest, and longest-lasting material that is the best option. The best option is, instead, a material that will not damage the original by contact or during necessary future removal, as well as one that offers the best possible physical properties described above. "Retreatability" is a fact of life. Magic bullets, everlasting treatments and formulas, and universal solutions are fictions belonging to a naive past. The best that can be done is to provide the means to slow the inevitable natural decay mechanisms affecting the materials.

An example of GCI work that applies this approach to research and treatment is a recent project in Prague. Institute staff, working with Czech conservation professionals, developed a conservation program to protect a medieval glass mosaic on the facade of St. Vitus Cathedral in Prague Castle. As part of the program, a coating to protect the mosaic was identified and adapted in collaboration with scientists at the University of California, Los Angeles. This multiple-layer coating does not affect the original materials, and it includes a surface layer designed to be easily removed when necessary. As such, it facilitates future treatments that will be dictated by the planned systematic monitoring of the monument.

Scientific research at the Institute is conducted in specialized laboratories. The Museum Research Laboratory is dedicated mainly to the analysis and study of works of art and their original technologies, as well as to specific aspects of their conservation. Another laboratory, focused on the development of new analytical technologies in the study of materials, performs work in Fourier transform infrared spectrometry, gas chromatography/mass spectrometry, elemental analysis, and thermal analysis/mass spectrometry. Preventive conservation research is performed in two laboratories specializing in indoor and outdoor environmental studies, pest control management, and control of microenvironments; several engineering and analytical chemistry techniques, such as liquid and ion chromatographies, are utilized here. Three other laboratories support the building materials research, particularly the studies of deterioration and preservation of stone, stuccos, mortars, and earthen building materials. Another laboratory, the electron microscopy laboratory, provides an array of techniques and methods essential to the study of the material composition of samples and the original manufacturing technologies of objects (microprobe), as well as environmental electron microscopy, which allows examination of deterioration processes in microscale.

Interdisciplinary Research

Conservators applying a multiple-layer coating to the medieval glass mosaic on the facade of St. Vitus Cathedral in Prague Castle. The protective coating was identified and adapted for use on the mosaic by GCI staff in collaboration with scientists at the University of California, Los Angeles. Photo: Eric Bescher.

The nature of conservation research requires the interdisciplinary involvement of different specialists within the field. As Giorgio Torraca, long-time deputy director of the International Center for the Study of the Preservation and Restoration of Cultural Property (ICCROM), has written, "effective interdisciplinary work is an absolute requirement for progress in conservation."

In GCI projects, scientists collaborate with conservators and art historians from the very first stages of the research. In many instances, scientific work in conservation, isolated from the practical experience of conservators, produces interesting and original data appropriate for a paper or a presentation but fails to result in something useful for actual conservation practice.

Clifford Price, a noted British expert on the conservation of stone, has observed that "there is no point in doing research unless the outcome can be applied in practice. This does not mean that there is no place for long-term, strategic research, but that any worthwhile research must contribute ultimately to the care and conservation of the heritage."

At the GCI, the emphasis is on applicability. Scientists provide essential information to conservators about deterioration causes, principal factors influencing the damage mechanisms, and compatible materials. Working with the conservators, they design conservation treatments and evaluate treatment performance.

In its laboratories, the GCI is conducting a series of tests on limestone samples to better understand the damage to porous stone that results from the interaction of water and salts. These before-and-after images illustrate the destructive power of that interaction. Photos: Eric Doehne.

At present, GCI scientists are engaged in fundamental applied research to conserve museum and collections objects, as well as building materials and structures. Current projects exemplify the collaboration between scientists in the laboratory and conservators. For example, we have refined analytical strategies to improve identification of organic materials in paintings; using a comprehensive gas chromatography/mass spectrometry method, we are able to identify complex mixtures of organic materials in paintings, detecting several different components using only one tiny sample. We have also evaluated new and promising treatments to improve cleaning of painted surfaces of objects and works of art. This research includes studying the consequences of the use of gels and solvent-based systems for cleaning painted surfaces. In these projects and in others, scientists and conservators gather to establish relevant research questions and objectives, as well as to identify fundamental issues surrounding the conservation treatments of the works of art in order to design experimental procedures and interpret the research results.

The concept of collaboration extends to organizations. In conducting its research, the GCI works closely with research institutions in other parts of the world. Through this interaction, Institute staff has the opportunity to develop and deepen its expertise in some applied research aspects of conservation science, as well as to engage in more complex and comprehensive projects. For example, in our research on lime mortars and plasters, we are working with scientists at the Raymond Lemaire Conservation Center at the University of Leuven in Belgium to jointly evaluate issues related to the characterization, carbonation rates and equilibria, and performance of lime mortars and plasters in specific field studies. In a recent project studying the protection of collections in humid, tropical environments, the Vitae Foundation of Brazil provided support for Brazilian conservation professionals to participate in the work. And the GCI's partners in its project on the preservation of earthen architecture include ICCROM and the Research Center for Earth Construction-School of Architecture of Grenoble, France (CRATerre). Each of these relationships enhances the ability of GCI staff to identify, adapt, and introduce recent scientific and technological advances into the field.

Deteriorating limestone at the Maya site of Tikal in Guatemala. The Maya commonly used this porous stone for construction. Photo: Eric Doehne.

Part of the hieroglyphic staircase at the Maya site of Copán in Honduras. GCI scientists are investigating the causes of the staircase's deterioration. Photo: Nicholas Stanley-Price.

The overall strategy guiding scientific research at the GCI is to offer methodologies that identify and address the specific causes of deterioration of a monument or a work of art, then to provide the specialist with the tools to design appropriate treatments or actions. Because individual works of art and monuments are unique, the solutions to treat their problems must be specific. An appropriate methodology to identify problems and evaluate potential solution options is the best contribution we can make.

In all cases the Institute is guided by the fact that the products of our work have to be accessible to the conservation community. We do not believe in expensive high technology for its own sake. Instead, we believe in the use of technology to produce and validate widely applicable, low-cost technological solutions. Our facilities and extensive collaborative work allow the Science group at the GCI to conduct studies that apply science and technology in a manner that contributes to a better understanding of the conservation needs of art and monuments worldwide. And because the GCI is a nongovernmental organization without primary responsibility for a particular collection, it has the flexibility to examine the broad problems of conservation and to allocate its resources to meet broader needs.

Kerstin Elert, a research fellow with the GCI, testing the oxygen permeability of a bubble made of high barrier film to determine its effectiveness. The bubble encloses a nitrogen atmosphere that eradicates pest infestations in museum objects. The GCI has been studying the uses of oxygen-free environments for use in storage cases and pest eradication. Photo: Alberto Tagle.

It is the prime function of a conservation scientist, writes Norman H. Tennent, a conservation scientist himself, "to provide knowledge or technical information which enables more effective preservation and conservation of cultural heritage." But the obligation of scientists involved in conservation work extends beyond research. "An effective conservation scientist must also be a teacher who communicates the relevance of the science that underpins good conservation," notes Tennant. "It is a poor conservation scientist who resembles the priest who was 'so heavenly minded that he was no earthly good.'"

Inherent within the GCI's scientific research efforts is the recognition of our obligation not only to share, in a broadly comprehensible way, the nature and results of our work but also to illuminate the ways in which science can serve the cultural heritage that enriches our lives.

Alberto Tagle is group director of science at the Getty Conservation Institute.

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Conservation Research

Research in the conservation field traditionally has focused on scientific work that investigates the nature of materials and their deterioration processes and that studies and develops new methods for the treatment of cultural heritage. This kind of research remains critical to conservation.

But conservation today is recognized as most effective when pursued in an interdisciplinary manner. In practice, such an approach means that other types of research in addition to the scientific are important to conservation efforts. Staff at the GCI regularly conducts diverse research that helps provide answers to complex conservation problems and illuminates conservation issues in general.

For example, bibliographic research is an essential part of any conservation project, be it in the laboratory or in the field. In each of the GCI's major projects, an extensive review of the literature is undertaken to create a comprehensive picture of the significance of the project's site or artifacts, the values attributed to the project's subject over time, and the extent of conservation work previously conducted. This bibliographic information helps guide the work and constitutes an important product of the project.

One area where broad research is vital is in the development of conservation strategies for historic cities; a number of issues must be considered that extend beyond the preservation of structures. The social and physical needs of the contemporary population, as well as the economic realities of the community, have to be considered. This requires conducting historical, social, and economic research. As part of its past work on historic cities, GCI teams have engaged in a variety of areas of research in order to better understand the complexities and compromises that accompany conservation in a living place.

Another area of research need recognized by the Institute involves questions of policy and the decision-making process, economic issues, and the changing social and cultural contexts in which conservation work is performed. With this area in mind, the Institute is investigating the economics of heritage conservation and how economic considerations—such as cost-benefit analyses and the desire for tourism revenue—shapes conservation work. This research encompasses the work of practitioners from a number of disciplines, including anthropologists, economists, historians, and policy experts, as well as conservation professionals.