This talk reports on the study of a diverse range of conceptual approaches and applied methods in North American and European preservation and restoration of outdoor bronze sculpture since the 1970s. Special attention is given to influence from government and cultural heritage agencies and from varied business, administrative and curatorial circumstances in the development and general adoption of the most common approaches to the care of outdoor bronze. The mutual influence of European and North American development is discussed.
Of particular interest for scientists and restorers are different assessments of the roles and desirability of corrosion products and applied systems on exposed surfaces, and the different criteria for aesthetic reintegration. Some restorers see danger in weathered “corrosion crusts,” where others see surface passivation and substrates for coatings. Some apply and maintain short-lived waxes while others build up robust lacquers, and others recommend no coatings at all. Some funders and restorers want “like new” appearance, while others are satisfied with enhanced coherence. The option of “no treatment” is gaining support. Each approach has its logic.
More interesting to conservation administrators and collection managers may be discussions that relate to planning, preservation and maintenance, agency development, and/or management and review of survey and treatment projects. A non-governmental agency founded by a lobbyist and staffed with an administrator and educators- Heritage Preservation’s Save Outdoor Sculpture program- has developed and promulgated systems and publications for communities-based needs assessment and education, and government and private support for public art projects. The Bavarian State Agency for Monuments Preservation (BLD) is a government research and oversight agency administered and staffed by conservators and conservation scientists. In the course of overseeing and carrying out monuments preservation in Bavaria and collaborating in surrounding states, BLD has surveyed, assessed, developed and published examination methods and criteria, treatment methods and materials. In general active agencies are very results-oriented; yet their goals and programs, their criteria for assessing results, and their impacts can differ significantly.
Mutual influence of European and North America has operated through international meetings and publications, and through expatriate internships, fellowships, employment and other collaborations. These include a number of papers on the condition and treatment of outdoor bronzes by various authors in the 1972 Madrid, 1975 Venice and 1978 Zagreb Triennial meetings of ICOM-CC; important Italian contributions such as the work on the bronze horses of San Marco, Venice; and Rieder’s article The Cleaning of Outdoor Bronze Sculptures in 1977.
In North America much spirited discussion occurred in several meetings: Corrosion of Artistic Works… Massachusetts Institute of Technology 1987, National Association of Corrosion Engineers’ Dialog 1989 and Dialog 1994, and Ancient and Historic Metals Getty Conservation Institute 1991. A decade of development concluded with the American Institute for Conservation’s 1992 symposium, Maintenance of Outdoor Sculpture.
In Europe, ICCROM convened its Paris symposium Conservation of Metal Statuary in 1986, Robbiola, Fiaud and Pennec in 1993 published their “New model for outdoor bronze corrosion…” at the ICOM-CC 10th Triennial meeting, and in 1993 Römich and colleagues began work reported in New Conservation Methods for Outdoor Bronze Sculptures, 1996. In 1997 Göteborg University published Strandberg’s very useful Perspectives on Bronze Sculpture Conservation. In 2000, BLD collaborated with sister agencies of Sachsen and Sachsen-Anhalt in Bronze- und Galvanoplastik, a truly remarkable contribution.
European and North American approaches to conservation of outdoor bronzes have been mutually influential from 1970s to present. The same types of factors have shaped each, with rather different outcomes. European approaches seem rather more conservator-driven and less interventive than North American, yet preservation and maintenance of outdoor bronze sculpture have been and remain diverse on both continents.