The Red Backgrounds of Wall Paintings from Isturgi and Cástulo (Jaen, Spain): A Multi-Technique Approach to Understanding and Improving Their State of Conservation

This contribution presents a multidisciplinary approach that encompasses contextualization, photographic, and graphic documentation, as well as a comprehensive characterization scheme focusing on the morphological, chemical, structural, and electronic aspects of the red panels from two significant archeological sites: Cástulo and Isturgi. The red panels, which constitute the predominant component of the paintings, are indicative of their conservation state and were characterized using various techniques, including several microscopies tools, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy. The characterization scheme revealed significant structural differences in the paintings, with hematite present in the samples from Isturgi and both hematite- and lead-containing components being observed in those from Cástulo. The organic components are primarily associated with the use of Paraloid during the extraction of the paintings. Notable differences related to the encrustations of carbonate species are also observed, which are more prominent in the paintings from Cástulo. The results enable a discussion of their state of deterioration and the identification of future lines of action for their conservation.