By Leslie Rainer

Murals are most commonly defined as wall paintings, works of art integrated into a specific architectural space. Art historian Francis V. O’Connor has emphasized the importance of a mural’s setting, writing that “a mural, unlike portable works of art, is an environmental artifact that was conceived in relation to its natural and/or architectural setting; the original site is an intimate part of its formal attributes.”

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The word mural is derived from the Latin word murus, meaning wall. Walls have long provided a direct support for aesthetic, political, and social ideas expressed with paint. Cave paintings could be considered the earliest murals, followed over time by wall paintings in tombs, temples, churches, civic buildings, and a variety of outdoor spaces.

Modern murals grow out of this long tradition. From the beginning of the 20th century, murals have had a significant presence in the architecture of the Americas. Artists like John Singer Sargent created great mural cycles for museums and libraries. The masters of the Mexican muralist movement—Diego Rivera, Clemente Orozco, and David Alfaro Siqueiros—produced works for public buildings. In the 1930s, under the auspices of the U.S. Works Progress Administration, artists were employed to paint industrial, agricultural, and social scenes on the walls of post offices, schools, and other public buildings. In the second half of the 20th century, social change, political activism, and the rise of the Chicano mural movement generated new impetus for murals in the United States. Artists gave voice to the Chicano population and recorded their history—otherwise largely neglected in mainstream education. Waves of artists of all backgrounds followed, creating a vast array of imagery around the country on the walls of freeways; parking structures; housing projects; and public, private, and commercial buildings. A large number of these murals are exterior works, created for community outreach and neighborhood beautification. Through redevelopment programs, percent-for-art initiatives that mandate financial support for artworks, and youth training programs, such funding of murals has led to an explosion of public art in cities and towns across America.

The Conservation Challenge

Over the past 30 years, a vast number of exterior murals have been created. Philadelphia is home to 2,500, Los Angeles to over 1,500—and there are hundreds more throughout the rest of the country. Today as these murals age, many require conservation treatment if they are to survive. Unfortunately, relatively little thought was given to the maintenance and conservation of these murals at the time of their creation. Maintenance was either not part of the plan, or it was not carried out as murals began to show signs of deterioration. Frequently, little funding is available for maintenance and conservation.

Modern exterior murals exhibit a range of problems that are complicated by the use of modern and untested materials. Artists have used paints and coatings that were not necessarily manufactured for longevity in exterior use; after 20 to 30 years, exposed to harsh outdoor environments, these paints are deteriorating. Compounding these problems is the fact that many murals are painted in places where maintenance is nearly impossible. Made to beautify the cityscape and to bring neighborhoods together, these works now show wear, and in many cases they are targets of vandalism.

A number of cities have begun to inventory and assess their murals. Los Angeles counts over 450 that were made in part or in whole with city funds, sponsored by various city agencies and community groups. These range from paintings in historic public buildings to mosaic, tile, and painted works on walls in schools, housing projects, and freeway underpasses.

Who is responsible for this public art? A city agency that commissioned a mural may lack the resources or interest to maintain it. Once a mural is painted on a wall, it becomes the property of the building owner. At the same time, the image and the copyright belong to the artist. As long as the artist is living, he or she also has a voice in the mural’s treatment.

Should conservation follow the strict guidelines used for museum pieces exhibited or stored in controlled environments? The answer, presumably, would be yes. However, with the many voices—community, city agencies, artists, and conservators—that contribute to decisions regarding the fate of a mural, this is a matter of debate. Is the objective to stabilize the paint and ground, or is it more appropriate to restore the mural to its original brightness and intensity, erasing its historic value in favor of a fresh appearance? When artists are still living and can be contacted, should they be responsible for their own work? If artists so desire, should they have the right to repaint their murals? In Chicago, a group of artists has carefully documented their murals from the 1970s and 1980s, and they repaint them when they become degraded. Do those murals, as a result, become new works of art with new dates attached to them?

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The Problems

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Environmental conditions are a major factor in mural deterioration. Freeze-thaw cycles and capillary rise affect the architectural support of the mural and lead to salt efflorescence, cracking, and lifting of the paint layers if incompatible paints or coatings are used and the mural extends to ground level. Impermeable coatings, like polyurethane (often used as an anti-graffiti coating), can perform badly when applied over a mural on a building that is affected by thermal fluctuations; the coating may crackle and lift, often taking the paint layer with it. Moreover, polyurethane cannot be removed from a painted surface without simultaneous damage to an acrylic paint layer.

In general, a mural should never be painted on a south-facing wall where direct and constant exposure to ultraviolet rays accelerates binder deterioration and paint fading. A mural painted on a wall with an overhang is likely to be more protected than one fully exposed. Conversely, murals painted on buildings with no overhang—where water may run down the wall with heavy rains—are at risk of water infiltration from above. Water infiltration can also occur with roof leaks, resulting in problems of salts, lifting paint, and drips and stains. Structural failure, too, affects wall paintings. Buildings that have settled or that are in seismic zones may show structural cracks, which can lead to water infiltration, followed by paint flaking and losses.

Acrylic paints used on exterior architectural surfaces break down over time and are not always compatible with their architectural support. These issues are similar to those faced by contemporary art in other forms (see Conservation, vol. 17, no. 3), but problems of modern materials are exacerbated when they are used outside. Severe breakdown of the paint binder can be seen on murals after as little as 10 years—especially those works exposed to direct sunlight. Fugitive colors are also a concern, particularly reds that have faded, dimming the intensity of a work. For example, one L.A. mural by Noni Olabisi, To Protect and Serve (1995), lost some meaning when the background of deep crimson, symbolic of blood, dulled over time.

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Mineral paints are more suitable for outdoor murals—there are exterior wall paintings from the late 19th century made with mineral paints that remain in good condition—but the paints are harder to find, and many artists are unfamiliar with them. As with the fresco technique, these paints are not film forming and do not inhibit the migration of water vapor through the wall. Thus they last longer.

Preventive conservation—such as preparing the wall properly and using high-quality, lightfast, and compatible materials—is fundamental. Other preventive actions (e.g., regular maintenance, graffiti removal, and community awareness) can help preserve murals. Much of the damage seen on murals is due to vandalism and a lack of maintenance. Sadly, regular maintenance is not always a priority. Jack Becker of FORECAST Public Artworks looked at funding strategies for percent-for-art programs initiated in the 1970s and 1980s and found that these programs commonly only began to consider maintenance 10 to 15 years after their founding.

Maintenance of murals is essential to their preservation. Maintenance can be administered by a governmental agency, or it can come from the artist or the community. Increasing the awareness of community members of their murals increases the art’s chance for survival, as does early assessment of problems and timely intervention. Everything—from sweeping around the mural and cutting back adjacent gardens to maintaining gutters and repairing wall damage promptly—helps preserve murals and discourages tagging with graffiti. If graffiti is left on a wall for a long time, it seems to signal others that it is a canvas for tagging. Conversely, prompt removal of graffiti usually arrests further tagging.

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Dealing with Impermanence

Is the removal and relocating of a mural an appropriate approach to the preservation problems of a mural? According to Paul Philippot—one of the foremost theorists in conservation and coauthor, with Laura and Paolo Mora, of The Conservation of Wall Paintings—“a wall painting is always an integral part of the architectural ensemble for which it was created and which in part defines it. The detachment of a wall painting from its architectural support constitutes dismemberment and is to be avoided by principle. The respect for the integrity of the ensemble in situ is the rule.”

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Museums around the world contain numerous fragments of murals that were removed from their walls and installed in another location, or placed in long-term storage. However, in most places this is no longer an acceptable method of preserving a wall painting. Current practice holds that works should be preserved in situ unless they are threatened with destruction. The Lovejoy Ramp murals, for example—created by Tom Stefopoulos between 1948 and 1952—were drawn and painted on columns of an overpass in Portland, Oregon. When the city demolished the ramp to facilitate development of the area, community members and a conservator worked together to preserve the columns, dismantling them and storing them. They are due to be reinstalled as public art on a nearby site.

In the Americas, there have been recent cases where murals have been moved. The options for removing a mural from a wall are either by strappo (tearing the paint layer from the support), or stacco (removing all or a part of the thickness of the wall with the work on it). Murals painted on canvas and adhered to the wall (marouflage) have been removed and rolled up for transport to be treated, stored, or exhibited in another location. In all of these cases, the mural is liable to suffer paint loss, as well as structural damage. Worse, though, it loses its context as part of the architectural ensemble for which it was created; at the same time, the site also loses meaning with the removal of the work.

With the impermanence of many materials being used today and the sheer number of murals on exterior walls, it is not possible to preserve all of them, and many may well disappear. At the time a mural was painted, community members were likely involved in its creation, or at least they had a kinship with it. Over time, though, a new generation comes of age or neighborhoods change, and the community may no longer have the same connection with the mural. Once a mural begins to deteriorate, if it lacks significance for the community, it may become a canvas for graffiti.If it is considered significant by community members or other groups, there is a greater chance of its preservation.

Documentation is one way to virtually preserve murals that are in danger of disappearing and to create an archive for future study. Indeed, with a high-enough recording resolution, documented murals could be reproduced to full size.

Treatment Options

As murals deteriorate, owners and agencies have several treatment options. They may ask the artist to repaint or restore the work, or they may call a conservator who could either treat the mural according to strict conservation guidelines or work with the artist to conserve and possibly restore the work. With contemporary murals, there are many instances of restoration or even re-creation.

Some artists have repainted their murals when they show fading, wear, or vandalism, especially when there is extensive damage that requires interpretation and repainting. Kent Twitchell is presently repainting his mural Strother Martin Monument, originally completed in 1972, accidentally painted over in 1987, and repainted in 1988. The current repainting shows modifications with changes in colors and materials—a 2003 version of the original. On the other end of the spectrum from repainting is traditional conservation, which aims to slow deterioration by stabilizing the paint layers, cleaning the surface, and minimally reintegrating the image. Significant interpretation of the image is best left to the artist to re-create. In the case of Magritte in Los Angeles (1984) by Noa Bornstein, conservators worked with documentation and original artwork from the artist to reintegrate losses in the image.

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The conservation of Dolores del Rio (1990) by Alfredo de Batuc is a good example of collaboration between conservators and artist that can serve to recapture the vitality of a work. The mural showed structural cracks, overall surface accumulation, deterioration of the paint binder, and fading of certain colors. Conservators filled the cracks, cleaned, removed a failing coating, and consolidated powdering paint. The artist, using lightfast colors, reinstated red and green details that had faded. Together the artist and conservators reinforced the brightness of the mural’s sunset.

This kind of balanced collaboration is vital to the conservation of a mural. The artist can provide material and visual information, and the conservator—trained in the analysis and diagnosis of complex conservation problems—can develop appropriate treatments. Several programs around the country—including the Metropolitan Transit Authority (MTA) in Los Angeles, the Wisconsin Arts Board’s Percent-for-Art, and the New York Public Art in Public Schools (PAPS)—have brought conservators and artists together from the beginning of the commission process. All require a review of the artist’s proposed materials, fabrication, and finishing processes. The MTA has conservator review, and conservation as well as maintenance are taken into consideration in the installation of the work. The PAPS program includes custodial training and emphasizes educating students with initiatives such as Conservation in Context, which PAPS Program Director Michele Cohen states, “underscores the need to contextualize the conservation of public art.” In these programs, the issues of conservation and maintenance are addressed even as the mural is being made.

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This leads to the question of specialized training. In countries with a long tradition of wall painting, specialized training for artists and conservators is provided in fine arts and restoration schools. Only a handful of U.S. schools have courses in mural painting; artists are often expected to apply their training in easel painting to murals, where the architectural system must be considered. Artists should be familiar with issues of location and exposure, wall preparation, and use of appropriate materials, and courses should address materials and techniques for murals, as well as conservation and maintenance issues.

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Training in mural conservation is also lacking in the United States. Conservation programs tend to specialize in works of art in a museum environment or architectural conservation—but not that hybrid of wall painting conservation. Mural conservators must understand systemic problems related to the structural issues of the building, environmental factors that affect pigments and binders, and material degradation of a variety of paints and coatings. They should also be versed in traditional materials and techniques of construction, plaster, and paint. With the number of murals now at a critical moment when they require conservation, there is a real need for training. But even so, the task of conserving wall paintings often requires a multidisciplinary team made up of architects, engineers, and conservators to successfully address the complex problems facing the wall and the wall painting.

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A Holistic Approach

The issues that directly or indirectly affect the conservation of murals must be approached from all sides and at all levels. As some cities are recognizing, there must be an administrative responsibility for maintenance and long-term care, preferably from the conception of the project. This includes keeping a complete inventory of murals, with full documentation, including information on the materials used. Rae Atira-Soncea, Percent-for-Art conservation coordinator of the Wisconsin Arts Board, has stated that “maintaining reliable information is the first step in conservation.” Artists can help by providing the appropriate funding agency with original artwork and images of the work upon completion. One way of managing this information is to create a database that can be updated over time that gives full information for every mural in a given city or region. In Los Angeles and Quebec, databases are being developed for the inventory and condition assessment of large collections of murals.

Relationships between artists and conservators should be cultivated and strengthened; arts administrators could encourage this relationship in a formal way, as the MTA does. The collaboration between artists and conservators should start at the time of mural creation, well before the need for conservation arises. Conservators can advise on the best paints to use from a materials standpoint; perhaps they can take this one step further by helping industry to research and develop appropriate materials for use in the creation and conservation of murals. At the same time, it is necessary to train more conservators in mural conservation. Conservation programs could incorporate courses on murals and architectural surfaces into their curricula.

In caring for exterior murals, conservation is not only a scientific and technical endeavor. As Julie Boivin, cocurator for the public art of Montreal, has written, “conservation has become a fundamentally social and cultural activity in the fullest sense. The public art equation in which artist, client, public, and site are indissociable must continually be questioned, evaluated, and perhaps modified. The conservation of contemporary public art might raise some of the most challenging issues and provide opportunities to observe how far we can take those ideas.”

Leslie Rainer is a GCI senior project specialist with extensive experience in the conservation of archaeological, historic, and modern murals.