Gilding on a 15th century stone relief from Dubrovnik: technical study vs. Cennini’s recipe

During 2016, the Croatian Conservation Institute carried out a demanding conservation and technical research on a 15th century gilded polychrome stone relief from Dubrovnik, attributed to Pietro di Martino da Milano (c.1410-1473). The process proved to be a valuable opportunity to better understand the materials degradation and the techniques used by the Master. Due to the difficulty of determining the existence of impregnation and ground layers, two experimental reconstructions were created as part of a student project – one based on the interpretation of research results obtained during the conservation treatment, and the other based on art technological source research, namely the Cennino Cennini’s recipe, CLXXIV. The aim was to evaluate the effectiveness of these layers on the final gilding and to get an insight into the Master’s experience via the “learning-by-doing” method. The experimental results indicate that the cause of the damages and the consequent fragility of the original relief, might have its origin in the absence of impregnation and ground layers.