Study and experimentation for a controlled laser cleaning of feathers

This work focuses on the scientific experimentation and practical application of a laser cleaning methodology for the macaw (Ara ararauna) feathers of an ethnographic bow with arrows from the Museum of Anthropology and Ethnography of the University of Turin. The fragility of the object and its unique degradation characteristics suggested the use of a very selective physical method, such as laser cleaning. Prior to the intervention, a comprehensive systematic experimentation phase was conducted including commonly used diagnostic techniques along with a rarely employed analysis for cultural heritage characterization: X-ray Photoelectron Spectroscopy (XPS). The aim of the experimentation was to gain a deeper understanding of the physical-chemical effects of laser irradiation. Through a dedicated experimental setup, optimal operating parameters for laser treatment of macaw feathers were determined. XPS analysis enabled the examination of the treated material and the assessment of potential surface alterations, thus allowing to precisely define the damage threshold. Following the comparison of different Nd:YAG(1064 nm) lasers, the Long Q-Switched mode provided better results and it was selected for the overall intervention. This laser ensures effective removal of deposits, selectivity and respect of the fragile substrate.