Caracterização dos frescos de pintura romana do Auditório do Mecenato e da Cittá Dipinta - Termas de Traiano para a sua conservação preventiva

Abstract

Characterization of Roman Painted Frescoes from Mecenate's Auditorium and from Città Dipinta - Traianus's Thermae for their Preventive Conservation - ABSTRACT: This master thesis is focusing on the archaeometric investigation and analysis of Roman Painted Frescoes from Mecenate's Auditorium and from Città Dipinta - Traianus's Thermae, to characterize the materials used in execution of the painting layers and mortar, for their Preventive Conservation. Mecenate's Auditorium and Città Dipinta fresco paintings are unique with their decorations which characterized by absence of the human figures and focusing on nature and topographical drawings. Both of them are located in archaeological imperial buildings in Rome. The main objective of this study was to characterize the fresco wall paintings through studying the painting techniques, the pigments used in execution of paintings, mortars characteristics at Citta Dipinta which will play role in the preliminary dating of the wall. Furthermore, determine the conservation condition and the previous conservation procedures that may severely affect the paintings in the future. Selected analytical and investigation techniques have been used for this purpose such as Optical – Stereo microscopy, Micro Raman Spectroscopy and Thermogravimetric analysis. According to the acquired data and its interpretation, a variety of pigments has been identified representing the color palette of Roman fresco paintings such as, Red Ochre, Cinnabar, Yellow Ochre and Carbon black; regarding the blue pigment it was challenging to be confirmed. For the mortars it was really unique with high strength and durability attributed to its hydraulic characteristics. A degradation product has been detected such as Gypsum on the surface of paint layers at the Auditorium, and layer of yellowish Paraloid acrylic resin was found and this is used in previous conservation. The results of the archaeometric study and the documentation of the degradation aspects at the Auditorium of Mecenate and Citta Dipinta paintings, enabled to propose a preventive conservation plan, to prevent the sites from more alteration and degradation and establish maintenance system for the future.