Integrated analytical approach to unveil the secrets of the recently discovered "Sphinx Room": a new piece of Domus Aurea puzzle
The recent discovery of the Sphinx Room, belonging to the Domus Aurea Esquiline wing, thanks to the framework given by the project "Non-destructive analytical studies at Parco Archeologico del Colosseo (Rome, Italy)", allowed to perform an analytical campaign, both in situ and on micro-fragments. The first aim was the archaeometrical characterisation of the painting materials. In fact, the analytical information on the wall decorations contributes to the overall comprehension of this
... of this extraordinary imperial architecture, and allows to contextualize the newly-discovered room inside the Domus Aurea complex. Moreover, further knowledge on the painting technique is achieved, which is of relevance for the general understanding of Roman mural decorations. The palette, composed of Egyptian blue, green earths, iron- and lead-based red, orange and yellow, calcite, carbon black, allowed to compare the Sphinx Room to Corridor 92 and Room 114 of Domus Aurea and to other sites in Rome. Furthermore, the employ of an organic binder in some spots can be put forward based on spectroscopic results, which does not exclude a wider use of the a fresco. Furthermore, a complementary methodological strategy was designed, in order to achieve a complete characterization of the materials. In addition to the well-known combination of in situ Raman and X-ray fluorescence analyses, Infrared Fourier Transform Spectroscopy was used, both in situ (Diffuse Reflectance) and in the lab (Attenuated Total Reflectance). The results confirm the suitability of this approach for the characterization of Roman wall paintings, where both inorganic and organic materials are simultaneously present.