IL CANTIERE DELLA “CA’ GRANDA”. LA LETTURA DELL’ESPERTO SCIENTIFICO

Abstract

The conservation works on the external facades of the so-called “Ca’ Granda” allowed to carry out a pilot yard, during which several cleaning methods have been tested; moreover it was possible to apply water-repellent and consolidation treatments, in order to monitor their performances. This survey was preceded by a complete characterization as regards Terracotta surfaces, which highlighted the presence of two different red finishes: the first was composed by gypsum and rabbit glue and second by siccative oil and lead white; both were pigmented with red ochre. Collecting all the observations, by a macroscopic and microscopic point of view, the choice of laser cleaning proved to be the most suitable. It used a Nd:YAG pulsed source, emitting at 1064 nm. Doing so, the assurance of the most complete conservation has been obtained, taking into account the particularly worrying state of conservation of the substrate.