Stucco marble altairs in Slovenia: materials, conservation, and meaning

While stucco marble altars are rather seldom to find on the territory of Slovenia, the existing (and known) ones present some of the most important examples of local baroque heritage, not least in terms of quality of their architectural parts, and usually, accompanying sculpture. Because of their rarity, conservators and restorers have little experience with them and it is therefore difficult to plan and execute their restoration or prepare the appropriate climate conditions of the church interiors. Moreover, the current state-of-research in art historical terms is not at a satisfactory level, since the first relevant studies were only published during the last twenty years. The lack of information can be overcome by combining conservation and art historical research with material analyses, which can give valuable information on materials composition and their state of preservation.  Present interdisciplinary project has therefore three important aims: (i) material analyses will provide information on rare traditional technology, and (ii) together with conservation-restoration studies they will prepare the framework and guidelines for planning and executing future preservation and restoration processes, while (iii) combination with the art historical analysis will help us to understand their importance and meaning, placing them in relevant regional and central European context. Such interdisciplinary accession to certain problems in heritage preservation is rather rare. On Slovene territory similar approach was taken during the European project “Tracing the Art of the Straub Family (TrArS)”, however less material identification was included, which is the main theme of present project.   After a careful survey and compilation of the list of relevant objects in Slovenia, the interdisciplinary project will aim to combine material, conservation-restoration and art historical research on 5 to 10 baroque stucco marble selected altars. Material identification, conservation-restoration examination and art historical research will be combined to obtain information about baroque technologies, particularities between different workshops and state of preservation of the selected objects as well as to propose the best conservation and restoration practices.  Material research will be carried out with methods allowing non-invasive and micro-invasive investigations. Analytical methods are selected to obtain as much information about material composition and possible degradation phenomena as possible: combination of microscopic (optical, scanning electron and immunofluorescence microscopies), spectroscopic (Raman, infrared and X-ray fluorescence spectroscopies) and chromatographic methods (GC-MS) will enable specific identification of historical materials, stratigraphy and degradation products, even for materials used in small amounts. By combining these results to art historical research, recipes and workshop-specific technologies will be revealed, as well as state of preservation of analyzed objects, which will reveal the most endangered altars and help to choose the most appropriate conservation-restoration treatment, possibly referring to sustainable conservation initiative (avoiding harmful chemicals, minimizing interventions, prolonging use of present materials).  The obtained knowledge will be shared with field professionals, students and interested public.