Consolidation tests on the graffiti of the Steri’s prison with nanotechnological Ca(OH)2 dispersed in iso-propanol

The combination of weathering and human activities often induce pyhisicochemical alteration on the surface of wall paintings. One of the most still largely used restoration techniques for these works of art, is based on the application of organic polymers. Due to their ability to stick detached and powdered pigments,these products provide an immediate consolidating effects. Unfortunately, both their aging and their pyhisicochemical incompatibility with the inorganic support can have serious consequences also causing further damage to the work of art. In this paper a new technological approach is presented based on the use of Ca(OH)2 nanoparticles dispersed in isopropanol. Some applicative test have been carried out onto the graffiti in the Steri’s prison in Palermo. After the application of the nanoparticles, SEM/EDX and water absorption tests indicate that the transpiration of the wall was maintained and that the open pores were not completely clogged, confirming that the nanolime dispersions is a good chemically compatible consolidant for wall paintings.