Monitoring and evaluation of damaging of traditional cleaning techniques of stones with 3D optical microscopy profilometry

In cultural heritage cleaning techniques are very important and delicate operations, and they are necessary every time the surface of the stone is covered with mostly soiling material to avoid further degradation or alteration. The problem is that often during the cleaning operations, not only the alteration and the degradations are removed, but also part of the materials of the building stones and ornaments , thus damaging it irreversibly. This paper investigates the effectiveness of 3D optical microscopy, used to monitor the surface of natural stones, such as Carrara marble, the Noto Limestone and the Serena Stone subjected to mechanical cleaning by micro-sandblasting. Therefore, we focus on the evaluation of the effects of cleaning on new natural stones, taken from the quarry, through 3D mapping and the roughness profile. The selected samples were analysed with the Alicona IF-Portable optical profilometer before and after cleaning to monitor any morphological changes induced on the marble substrate.