Methodological approaches for the in situ evaluation of conservation treatments on outdoor surfaces

While the quality of a conservation intervention is a multifaceted concept, it can be operationally defined through efficacy and durability to ensure objective measurability. This paper proposes a methodological procedure to quantify these indicators using non-invasive on-site techniques. The research is divided into two parts: a monitoring campaign on mural paintings in Dozza (BO), focusing on the artwork Ombre nella stanza (1965), and a subsequent validation phase under controlled conditions on test-areas. The procedure, based on the use of portable Raman spectroscopy, and measurements by contact sponge method and contact angle for the wettability, was tested. The results indicate that the methodology, despite being sensitive to climatic fluctuations and surface irregularities, offers essential data on treatment performance and represents a viable protocol for longterm monitoring.