Removal of overpaintings from easel paintings using LQS Nd:YAG laser

The removal of overpaintings from valuable easel paintings represents a very difficult challenge, which is traditionally approached using solvents and moderate mechanical actions. Here, we explore for the first time the potential of Long Q-Switching Nd:YAG (1,064 nm) laser with a pulse duration of 120 ns for selective ablation of overpainting layers. Mock-ups were prepared in order to approach in a systematic way a concrete uncovering problem concerning a modern painting on canvas. The former were prepared according to the stratigraphy and material compositions of the latter, as measured using optical and ESEM-EDX microscopy along with infrared and portable Raman spectroscopy. The parameterization achieved on the mock-ups allowed interpreting and maximizing the selectivity of the laser conservation treatment carried out on the real case.