Lasers in Cultural Heritage: The Non-Contact Intervention

Summary

Conservation and protection of works of art as well as of rare remnants of natural history has turned more and more into a race against time. Mechanical and chemical methods are involved in traditional conservation treatments. Contactless cleaning by lasers, on the other hand, is a new and prospering field of laser material processing. It allows avoiding mechanical disruption and the disadvantage of cleaning fluids which could cause potentially long-term degradation of the substrate or health hazards. The high-precision deliverance of laser radiation to morphologically and chemically inhomogeneous artefact surfaces – even down into the nanometre range – allows an unprecedented treatment quality by providing the base for repeatability of this treatment during the upcoming centuries of civilization.

Laser cleaning basically is a phase separation process driven by laser radiation. There exists experience in paint removal, and the restoration of building facades, stone and metal artefacts. More recently, the contactless laser cleaning of biogenetic fibre substrates such as paper, parchment and textiles has been approached. These biogenetic surfaces constitute the most sensitive and chemically fragile substrates studied up to date. They require ultimate thermal energy localization such as, e.g., minimized heat-affected zones. Therefore, the application of femtosecond laser pulses may play a future role in the context.