By Jeffrey Levin
In 1826, King Ludwig I of Bavaria began work on a new building to house his extensive collection of European paintings. The Alte Pinakothek was constructed on a site that was then well outside the city of Munich, a controversial decision at the time. One reason for the choice of location was simple: It was believed that the clean air would better preserve the paintings. The decision was, in a sense, an act of preventive conservation.
Until recently, conservation as a profession devoted itself almost solely to the care of individual objects. Mending or restoring an objectwhether a Roman bronze, a painting by Rembrandt, or a Chinese textilewas the primary function of the conservator. Today the demands for conservation can no longer be met satisfactorily by this approach. As both the number of museums and the number of objects within museums proliferate, concentrating exclusively on individual objects severely limits conservation care for the bulk of a collection. Even the most generously endowed institutions lack the financial and personnel resources to provide individual attention to every object in need. For those institutions with fewer funds, sustaining any conservation program remains a secondary or tertiary consideration.
If a major portion of our heritage is to survive, it must be cared for collectively rather than individually. For the conservator this means focusing on ways of preventing or slowing the deterioration of objects through control of the collections environment. It means, in short, preventive conservation.
Advantages and Obstacles
Preventive conservation can be defined as any measure that prevents damage or reduces the potential for it. It focuses on collections rather than individual objects, nontreatment rather than treatment. In practical terms, the handling, storage, and management of collections (including emergency planning) are critical elements in a preventive conservation methodology.
In the long term, it is the most efficient form of conservation, not only for museums, but particularly for libraries and collections of ethnographic, natural history, and geologic materials. With comprehensive preventive conservation, the need for individual treatments can, over time, be reduced to more manageable levels, putting personnel and financial resources to more effective use.
Despite its advantages, preventive conservation even where understood is more accepted in theory than in practice. The rate of deterioration in a group of objects can be slow and not fully appreciated except over long periods. Because the deterioration rate is difficult to quantify, the results of preventive conservation are not easily measured, nor are the results visually dramatic since preventive conservation does not involve improving the appearance of objects. In comparison, attending to the immediate conservation needs of an important or frequently exhibited piece can seem far more significantand urgent.
There are other institutional issues as well: The focus, in this age of limited resources, is often on survival. While preserving collections is obviously essential, for many museums and other collecting institutions conservation is not the primary concern.
"Museums are trained to survive," observes Marta de la Torre, Director of the GCI Training Program. "In order to survive, you have to justify your existence. Organizing large exhibitions is much easier to justify than conserving objectsbecause, in fact, conservation is not an end in and of itself. It's something that you do so that you can use those objects for another purpose." By seeking to control a museum's environment, preventive conservation, in the short term, can require a substantial outlay of funds. It means putting money into things that may have no visual impact, and therefore lack appeal to the public upon whose support the institution depends.
"The easiest thing in the world is to create a museum," says Paul Perrot, the director of the Santa Barbara Museum of Art. "The next easiest thing is to add galleries to it. But when it comes to the operation of these gallerieswhether it's the guards, the curators, or the conservatorsthe funds are not there because there's no glamour to it."
These issues, while serious, are not likely to completely obstruct the movement toward preventive conservation, in part because few alternatives exist. Already there is a growing body of scientific research that is leading to practical applications. Nevertheless, for preventive conservation to be effective for a particular collection, technical knowledge has to be matched with an administrative commitment to integrate preventive conservation into an institution's operation.
Acquiring Technical Knowledge
The scientific research framework for preventive conservation involves four progressive stages: 1) identifying threats to collections, 2) substantiating the risk, 3) identifying cost-efficient means to measure the risk, and 4) developing methods to reduce or eliminate the risk.
The basic problem for collections is object deterioration. "Objects deteriorate from either internal forces or external influences," explains Jim Druzik of the GCI Scientific Program. "Of those two, the external influences on an object are vastly larger than the internal instabilities. Things that have existed for half a millennium have very little residual internal instabilityso when they begin to deteriorate, it's purely an environmental effect."
The first step, then, is analysis of the museum environment. It is precisely in this area that the GCI Scientific Program has concentrated much of its efforts. Following a 1984 study, with the California Institute of Technology, on the relationship between outdoor and indoor concentrations of ozone, the Institute examined a number of outdoor pollutants and their penetration into the museum environment, research also conducted collaboratively. These investigations led to a series of studies on indoor-generated pollutants. "More and more, indoor-generated air pollution is becoming an issue that the conservation field wants to have resolved," says Druzik. "It seems every time one turns around one sees a bronze or other susceptible material corroding in museum storage in what is supposed to be a stable environment. Corrodants such as formaldehyde, and formic and acetic acids are being liberated by wood products and attacking a wide range of diverse materials."
With outdoor- and indoor-generated pollutants, a number of threats have been identified and the risks substantiated. The next stagefinding inexpensive means to measure the riskshas also been completed.
"We've identified, and called to the attention of the conservation field, low-cost, highly sensitive monitors," Druzik reports. "The next step is developing efficient, clever control techniques that can be applied in historic houses, older buildings, storage rooms, and display cases where the curator or conservator simply does not have the advantage of a full blown air conditioning system with particle and chemical filters built into it."
Microenvironments have been the subject of several GCI projects, including the development of a prototype display case for the Royal Mummies at the Cairo Museum and a study of the optimum storage conditions for the Dead Sea Scrolls at the Israel Museum in Jerusalem. The knowledge acquired in both projects has wider applicability for the preservation of organic materials.
In another area of preventive conservation research, the GCI conducted a joint study on pest control with the University of California, Riverside. The study quantified and confirmed the effectiveness of pure nitrogen as an "extremely promising" alternative to toxic chemical pesticides in microenvironments.
A major environmental factor for any collection is the design of the building housing it. Many of the world's museums and other collections are located in humid environments where North American and European design solutions to environmental control are too costly and architecturally inappropriate. Recognizing that much indigenous architecture is designed in a way to maximize human comfort with minimal mechanical systems (or none at all), the Institute has begun a study of passive and semipassive systems in tropical countries. Its findings could help lead to the development of cost-efficient environmental controls.
A Basic Approach
Preventive conservation does not always require expensive or complex care strategies. In many institutions, much can be done by applying common sense.
For objects in storage, reducing the potential for physical damage can be achieved through such modest procedures as restricting access, exercising care in handling, and whenever possible placing objects in individual boxes or containers.
When it has been determined that some material within the museum environment is producing corrodants, the obvious course is to remove the offending material. If this is not easily done, either sealing off the material or placing some barrier around it can reduce the potential for harm. Alternatively, creating a protective barrier around the objects can help minimize long-term damage.
Routine building maintenance can serve the cause of preventive conservation. Insuring that windows and roofs are in good repair can prevent moisture damage and help moderate temperature fluctuations that place stress on objects. Keeping both exhibition and storage space clean and free from dust (as well as from insects and rodents) is essential. Improving ventilation and air circulation through the use of low-tech fans and filters will also benefit a collection.
The Managerial Component
Because preventive conservation relies greatly on controlling the museum environment, it involves decisions beyond the conservator's traditional authority. "If you're going to control your environment you have to focus on your building and the different envelopes of protection," says de la Torre. "It might be a question of reviewing the heating and air conditioning systems (if those exist), or creating new storage, or changing the exhibition cases, or controlling the visitor pattern. You have all these things that are really not within the realm of the conservator. It's an administrative decision."
Since 1987, the GCI has offered an annual course in preventive conservation to mid- and senior-level conservators. The approach is macro to micro, beginning with an assessment of the building envelope and working down to the creation of microenvironments. While technical information constitutes a major portion of the course material, the importance of conservators being skillful advocates of preventive conservation is also emphasized.
Kathleen Dardes, a conservator by training, coordinates the course. She believes that for preventive conservation to be incorporated into museum operations, conservators must not only develop collection care policies, but convince others of their necessity. "You can be as clever as possible when it comes to dealing with technical matters, but if you can't speak about these things to the director in language he or she can clearly understandwhich means understanding the financial implications as welland if you can't communicate to curators and exhibition designers, and if you're not prepared to work with museum colleagues, then nothing's going to happen. It makes no difference how much you know."
De la Torre concurs. "We need to start selling preventive conservation as a feasible and viable alternative to the management of collections," she says. "We need to start talking very convincingly to curators and museum directors, saying, if you're going to be putting new demands on the collections, you must make sure you're protecting them as welland here are new methods of protecting them that are less expensive and more efficient."
At the same time, institutions need to foster a general appreciation of collections care. Lawrence Reger, director of the National Institute of Conservation in Washington, D.C., thinks the public has a genuine interest in the more "hidden" aspects of a museum's operation, and that institutions can do a better job of sharing the conservation process with the public. Reger believes museum patrons are now more receptive to supporting a museum's operational needs. "People want recognition," he explains. "I think they're willing to take on the redoing of a storeroom, as long as they get some kind of recognition. I think our goal has to be to promote this and help institutions bring this to the fore."
To Preserve and Pass On
Like nature conservation, preventive conservation of cultural heritage requires a change in attitudes and habits. The first level of awareness is simply understanding what preventive conservation means; the second is accepting it as a legitimate collections care strategy. The final and most important stage is when preventive conservation becomes an integral part of an institution's consciousness and is put into practice routinely.
Within the last decade the number of U.S. organizations promoting preventive conservation awareness has grown. Their ranks include the American Institute of Conservation, the Institute of Museum Services, the National Gallery of Art, and the National Institute of Conservation (NIC). In 1990, the NIC and the GCI concluded a two-year project to develop a methodology for museum professionals to amass and evaluate information on the condition of their collections. The project report, The Conservation Assessment: A Tool for Planning, Implementing, and Fundraising, is now being used by museums and federal funding agencies in the U.S. as a basic guideline for undertaking conservation assessments. But preventive conservation holds perhaps the greatest potential for institutions located in less affluent regions of the world, where the funds and personnel for individual treatments are in short supply. As Reger observes: "In countries with very limited resources, this is, frankly, the best approach to take."
There is, however, no collecting institution that would not profit from a preventive conservation program. "After all," says Paul Perrot, "preserving cultural objects for the future is a fundamental part of a museum's mission. Our historic charge is to make sure that these resources are not only collected and studied, but preserved and passed on." For that reason, says Perrot, preventive conservation "is good business, as well as effecting an ethical concern for objects that are within our care....We will certainly not arrest the march of time, but we can slow it down sufficiently so that these objects can be more true to themselves in years to come."
Ozone, frequently employed by cleaning companies and rescue teams to combat odors resulting from fire or flood, is known to be a high risk chemical that should, under no circumstances, be applied to museums, libraries, or other irreplaceable collections. Though thought to be a modern and efficient cleaning agent, ozone is actually an irreversible and highly destructive treatment that can damage and even destroy cultural property.
For some time, scientists believed that ozone was dangerous principally as a secondary pollutant in urban air. In 1984 the Getty Conservation Institute and the Environmental Quality Laboratory of the California Institute of Technology undertook a three-year study of the effects of photochemical oxidants on artists' materials, with special attention to ozone and nitrogen dioxide. Results, published extensively in the literature, were conclusive that both pose major risks for collections.
Recent events, however, indicate that ozone continues to be used in some museums. Reports are coming in from institutions in the U.S. and in Europe that ozone is still proposed for use in air conditioning systems and as a cleaning agent for smoke and water damaged materials. In one recently reported case, ozone-induced destruction of objects made of cellulose, silk, wool, leather, and metal led to litigation.
Ozone should not be used near materials of value, whether natural or cultural, organic or inorganic. For further information, please feel free to contact James R. Druzik, Conservation Scientist, the Getty Conservation Institute.