Author(s)

M.I. Cooper, D.C. Emmony & J.H. Larson

Abstract

The evaluation of laser cleaning of stone sculpture M.I. Cooper," D.C. Emmony," J.H. Larson^ " Department of Physics, Loughborough University, Loughborough, UK * National Museums and Galleries on Merseyside, Liverpool, UK ABSTRACT A Q-switched Nd:YAG laser has been developed to clean polluted stone sculpture. Results are presented showing the controlled manner in which polluted layers are removed from the sculpture without damage to the underlying stone. The absorption of laser radiation at 1.06jam by a black encrustation has been shown to be three times that of a clean limestone surface. Measurements of the threshold laser fluence (energy density) for surface material removal show that there exists a range of fluence within which it is possible to clean the sculpture without damage to the stone surface. The amplitude of the shock pulse generated in air by the sudden ejection of material from the polluted surface has been monitored to show that as t

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