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Laser cleaning of an eighteenth‐century parchment document

Abstract Laser cleaning of a late eighteenth‐century parchment document has been carried out. A Q‐switched Nd:YAG laser emitting laser radiation at a wavelength of 1.06 μm in pulses of 10 ns duration was used to remove soiling from the surface of the document; results were compared with those obtained using more traditional methods: abrasive cleaning and wet cleaning. Thermochemical analysis (shrinkage temperature measurements) and chemical analysis (amino acid analysis) have been carried out on laser‐cleaned areas to assess any detrimental changes to the structure of the parchment resulting from exposure to laser radiation. The interaction of laser radiation with three ink types on the document is also discussed. The results of this work suggest that laser cleaning at 1064 nm offers an extremely sensitive alternative to traditional methods of cleaning parchment documents in a relatively stable condition.