Pour une connaissance des peintures murales anciennes : des recettes de fabrication aux analyses physico-chimiques

Wall paintings may be studied accorded to 3 complementary investigation ways: documentary information, visual examination of murals and analysis of their materials.The written sources present different types. For Antiquity, treatises concern mainly agriculture and architecture and provide a significant collection of words for rendering of murals. For the medieval period, the nature of texts is more miscellaneous, technical manuals, chronicles, construction accounts, encycloaedias, architectural books. The terms used for rendering and its process are not firmly established and few information are given about its preparation. So, it is relevant to study archaelogical vestiges to carry out technical points of fabrication murals. It is a long time ago that restorers follow this way, nothing carefully technical information observed. Besides, the chemical analysis of murals gives additional information on the pictorial technique itself (fresco, secco, mixed technique), mixtures of pigments, the use of binders and the addition of specific organic compounds. The nature of pigments deduced from painting books is problematic because the same name may be associated to different products and, inversely, the same product may be called by different names. Consequently, the request to analytical studies of pictorial components is necessary to establish a true dialogue between archaeologist and analyst to choose the most suitable experimental approach for each wall painting.