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The use of laser cleaning to preserve patina on marble sculpture

1996; Taylor & Francis; Volume: 20; Issue: 1 Linguagem: Inglês

10.1080/01410096.1996.9995100

0140-0096

Martin Cooper, John Larson,

Building materials and conservation

Abstract The cleaning of marble sculpture is often complicated by the presence of a patina; an alteration to the marble surface as a result of ageing, environmental change (eg exposure to a polluted environment) or artificial means (eg staining with tea or coffee). When faced with cleaning a patinated marble sculpture the conservator has the difficult tasks of deciding what constitutes the patina and whether it should be preserved. The choice of finish will depend on factors such as experience, technical and historical knowledge, cultural background and access to analytical facilities. The development of laser cleaning techniques during the past ten years has given the conservator the ability to clean marble sculpture without damaging the patina. This paper describes different forms of patina, from the natural ageing of ancient Greek sculpture to artificially aged eighteenth century restorations. The fundamental ideas behind laser cleaning of marble are described and case studies presented which demonstrate how the technique can be used to remove layers of dirt without disturbing the underlying patina. A case study is also described in which it was desirable to remove the artificial patina. For this purpose steam cleaning was found to be a more appropriate technique.