The goal of heritage conservation is to preserve for all eternity the objects thought of as the world’s patrimony (Appelbaum 2007). In this process, there are a myriad of different possibilities for the goals of the conservation treatment as well as the actual treatment methods and materials. Just as architectural historic preservation theory has evolved, so has conservation theory. Today, many of the key attributes of heritage conservation are similar to the concepts of future-proofing and resiliency.
By the middle of the twentieth century, the understanding of restoration evolved to include the functional restoration of a work of art and architecture as well as painting and sculpture. Cesare Brandi writes about art and architecture as equally valid works of art. However, the functional properties are still held secondary to the “primary or fundamental aspect that respects a work of art as a work of art” (Brandi 1996a, 230). In contrast to Viollet Le Duc’s definition of restoration, Brandi holds that “restoration is the methodological moment in which the work of art is appreciated in its material form and in its historic and aesthetic duality, with a view to transmitting it to the future” (Brandi 1996a, 231). <<Edits to avoid dangling modifier.>>Brandi suggests that for buildings, the exterior appearance is primary, but that, in line with modern preservation requirements and designation of significant features, interior walls and structures may be altered to improve the building. This is important to the understanding of future-proofing and resiliency because it allows for flexibility and adaptability as well as the extension of service life, reduction of obsolescence, fortification, and increased durability and redundancy.
Brandi goes on to say that while “patina documents the passage through time of the work of art and thus needs to be preserved,” the patina should be an “imperceptible muting” of the original materials and must be brought into equilibrium with the original materials (Brandi 1996b, 378). Brandi’s intent is that the patina should not overwhelm and disguise the original, nor should patina be completely removed, but rather a balance must be sought between the two. This approach promotes the understanding not only of the original material but also the aging and interventions that is it has been subjected to over its history.
For Philippot, it is the authentic relationship between the past and the present that must be integrated “into the actualization of the work produced by the intervention” (Philippot 1996c, 225). This is also very similar to the concept of promoting understanding of the historic structure both before and after rehabilitation. Most important here is recognition and respect for the Gesamkunstwerk, or “unity resulting from the cooperation and collaboration of the various arts and crafts” that made the historic building (Philippot 1996a, 271). A natural consequence of this approach then becomes evident when considering lacunae, or missing pieces, and new interventions. These interventions should be made in such a way as to “reestablish continuity … while being easily identified on closer inspection” (Philippot 1996b, 359). This again underscores the importance of understanding the evolution of an historic structure.
Conservation theory has evolved to understand that “each treatment, or even non-treatment, nevertheless involves an interpretation of the object” (Van de Wetering 1996, 193). “Restoration has a certain autonomy independent, to some extent, from the artist’s intentions” (Van de Wetering 1996, 196). However, like Ruskin’s philosophy, Van de Wetering also holds that there is a “growing awareness that we will never understand the artist’s intentions to their full extent and that consequently our interpretations … never entirely cover the truth” (Van de Wetering 1996, 196). The restoration approach will thus vary; depending on the subject of the rehabilitation, different approaches may be appropriate. One approach, that of the collector, “prefers no restoration over authentic appearance,” or, alternatively, one recognizes that “interventions are often inevitable” and are the “concrete manifestation of an interpretation” of the historic object (Van de Wetering 1996, 197). Like Brandi and Philippot, Van de Wetering argues for the ability to understand the original aged object as well as its history, and, further, that this be conveyed to future observers.
Appelbaum suggests that there are potential differences between the “ideal state for the object” and the “realistic goal of the treatment” (2007, xx) The goal of conservation is to protect the object, extend its service life, and reduce its obsolescence by making the object desirable to keep (Appelbaum 2007, xxvii). As noted by Van de Wetering, a treatment involves an interpretation. A treatment, then, is “an interpretation chosen to enhance the meanings for which the object is valued and to accommodate its intended future” (Appelbaum 2007, xxi). “Treatments that improve aesthetics, usability, or lifespan of an object all increase its utility” (Appelbaum 2007, xxvi). Appelbaum goes on to say that “slowing an object’s deterioration also increases utility,” “an object that cannot be used … provides no benefit,” and “treatment is supposed to provide the physical strength to make those improvements last” (Appelbaum 2007, xxvii). Appelbaum’s statements contain many references to future-proof concepts, including preventing deterioration and decay, reduced obsolescence, and extension of service life, among others.
Implicit in the dozens of cultural heritage policy documents that address both heritage conservation and historic preservation are the doctrines of minimal intervention, reversibility, and differentiation. The concepts of reversibility are embedded in the Secretary’s Standards, the Venice Charter, and multiple other documents. Yet, as Muñoz Viñas points out, true reversibility is not possible and the concept is thus evolving to that of “removability” or “retreatability” (Muñoz Viñas 2005). Indeed, the phrasing of Rehabilitation Standard 10 already softens the relentless intent of reversibility by allowing for the “essential form and integrity” of an historic property to be returned (Weeks 2000). Minimal interventions are typically recommended to prevent loss of original historic fabric. Article 13 of the Venice Charter requires that additions do not “detract” from the historic building or its context (ICOMOS 1964). Similarly, the Secretary’s Rehabilitation Standard 7 requires that treatments use the “gentlest means possible” (Weeks 2000). Differentiation is explicitly included in the Secretary’s Rehabilitation Standard 9: “the new work shall be differentiated from the old” (Weeks 2000). Articles 9 and 12 of the Venice Charter speak to differentiation as well, requiring that “work which is indispensable must be distinct” and “distinguishable” from the original historic fabric (ICOMOS 1964). In the discussion of the concepts of future-proofing and resilience, the doctrines of minimal intervention, reversibility, and differentiation may be incorporated through inclusion of cultural heritage policy documents.