Underlying Mechanisms in Laser Techniques for Art Conservation: Two Improved Cleaning Methods

摘要

Optimisation of restoration techniques employing lasers is dependent on the selection of laser wavelength, cover fluid, pulse duration and method of application. This affects the mechanisms operating during the removal process and hence its efficiency. The risk of unwanted side effects will be more or less controllable depending on the mechanism of removal. This paper reviews laser removal mechanisms relevant to art conservation and outlines experimental work on the cleaning of polluted marble while employing two new cleaning methods: angular removal and laser shock processing. These two new methods both show clear advantages over conventional cleaning at normal incidence. A model for each method is proposed and the improvement in performance is quantifed. The relevance of the new techniques to art conservation is clearly outlined.