A study on materials and painting techniques of 1930s Italian mural paintings: two cases by Mario Sironi and Edmondo Bacci in Venice

ABSTRACT This study deals with two examples of the modern Italian Muralism, an artistic “movement” which took place in Italy at the beginning of the XX century and culminate in the 1930s during the fascist period. The case studies here presented were executed by Mario Sironi (1885-1961) and Edmondo Bacci (1913-1978) in Venice in representative public places, as they were given a community's role by the fascist propaganda especially addressed to young people. After the Second World War, the fascist symbols were eliminated and the murals partially sank into oblivion. This neglect and several unorthodox restoration treatments led the murals to the actual bad state of conservation. In recent years, they have been re-evaluated for their artistic value and, therefore, studied to know the materials used and the painting techniques in order to understand their conservation needs and plan sustainable conservation projects. Although the artists declared to paint a fresco (this production technique was considered the most appropriate at that time since it was the expression of the Italian traditions), the analytical results showed that the artists used tempera techniques: Sironi used egg yolk, casein and gum Arabic with industrial zinc, titanium, chrome and iron-based pigments and applied them on a fresco background; Bacci used commercial oil colours on a dry cement mortar. Furthermore, the actual conservation problems are mainly related to the poor adhesion of both original and non-original painted layers: both the murals suffered for conservation treatments in which synthetic materials were used to consolidate the painting layers but also to repaint and remake several original areas.