Two case studies of the manufacturing techniques & conservation of Baroque wall painting in Malta : Leonello Spada & Mattia Preti

Abstract

This dissertation is based on the findings of an analytical investigation into the constituent materials and techniques of two Baroque wall paintings in Malta. Both cycles, painted by Leonello Spada (1576-1622) and Mattia Preti (1613-1699) are situated in the capital city, Valletta, in the Magisterial Palace and in St John's Co-Cathedral respectively. Spada and Preti were summoned to Malta by the then Grand Masters of the time. However they adopted two completely different techniques of painting - fresco technique and oil directly on stone. These two cycles of paintings were selected as case studies to better understand the methodology of wall painting in the 1600s in the Maltese Islands. The aim of the study was to reveal the manufacturing techniques of these wall paintings (through graphical documentation, mapping and archival research), the constituent materials used by Spada and Preti (through scientific analyses to determine preparation, pigments, binding media), and the restoration interventions carried out over the years and the present state of conservation (through examination of detachments and delamination of the paint layer, salts, flaking paint). Historical research, visual observation of the paintings and diagnostic investigations on the samples collected from these were carried out in parallel. In the Magisterial Palace, four quadrants were chosen from the Green Room. Spada adopted materials available in Malta, and painted in fresco technique. The quadrants have been subjected to many restoration interventions and are in a poor state of conservation. The study of Preti's wall paintings focused on the lunette on the internal facade of the Co Cathedral. The stone was covered in a priming layer, composed of oil, and Preti painted in oil directly on this. The painting has also been subjected to restoration interventions in the past. Currently the lunette painting is in a stable state of conservation.