Stucco Forte in Venice between the 16th and 17th Centuries: The Case Study of Addolorata Chapel Stuccoes in San Pantalon's Church

Stucco samples of the 17th century were collected from the Addolorata Chapel in San Pantalon's church, which represents an important example of the stucco forte technique in Venice. Stucco forte is usually made adding powdered lime and marble to the gypsum base mixture. However, the exact recipe remain in most cases still unknown as often related to the knowledge and experience of the artisans [1]. The aim of the present work is to characterize and study the chemical-physical composition, the working techniques and the conservation state of the stucco forte in Venice. The samples were subjected to optical and electrical microscopic observation (OM, SEM-EDX), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TG-DSC), and mercury intrusion porosimetry (MIP). Gypsum, and calcium carbonate were found as major components with presence of magnesium carbonate and traces of hydromagnesite. Magnesite and hydromagnesite do not develop within the normal carbonation processes suggesting that magnesium carbonate was intentionally employed for improving the material characteristics.