Mural painting configures appearance, image, colour, decoration and symbolism of the architectural and archaeological Cultural Heritage (CH). Its compositional complexity makes it susceptible to the common deterioration agents affecting CH materials. In the current context of global warming, this susceptibility is increased due to the contribution of atmospheric pollutants and greenhouse gases to the formation of surface deposits that not only prevent the correct reading of the artwork, but also compromise the stability of the pictorial layer. When these exogenous deposits must be eliminated, according to the conservator’s criteria, to ensure the conservation of the painting, there is an urgent need to apply cleaning procedures that allow the maximum elimination without causing damage to the pictorial work. This procedure should follow a clean technology that helps to minimize industrial emissions.
Among the current cleaning methods in CH, laser ablation allows the removal of surface films in a localized, gradual, and selective manner without waste generation (environmental friendly). Its effectiveness and harmfulness have been extensively studied for removing surface deposits on rocks, but sparingly for cleaning of ancient wall paintings. The compositional complexity of these paintings, composed of inorganic pigments and organic binders, with different physical and chemical behaviours under laser irradiation, makes very difficult to draw clear conclusions about which are the mechanisms that make some paintings more susceptible to laser radiation than others.
Moreover, the scientific information about in situ laser cleaning performed on real paintings is very limited, probably due to this lack of solid knowledge about laser-painting interaction. This project, of a strong multi and interdisciplinary nature (three areas of knowledge converge: civil engineering and architecture, laser applications and fine arts) aims to investigate the laser painting interaction in a systematic and gradual way, investigating:
The response of the materials composing the painting separately (pigments and binders) to the irradiation considering different lasers, wavelengths and pulse durations.
The response of the whole painting, with a deeper prior knowledge about the susceptibility of each material. Knowledge on the irradiation conditions that generate the least damage to the paintings will allow a third part which is focused on cleaning of painting dosimeters and a real artwork.
