Uncovering the illegible: multi-analytical approach to reveal paint stratigraphy of corroded signposts from the Auschwitz-Birkenau State Museum

Abstract Object discoveries from the Auschwitz-Birkenau State Museum (PMA-B) in Poland challenge the efforts to preserve paint on corroded steel supports. The objects have been exposed to outdoor weathering conditions and then buried for about 65 years. This caused severe damage, such as corrosion and paint delamination. The fragile condition of such cultural heritage objects makes their preservation difficult and comprehensive studies for paint conservation are lacking. Additionally, a thorough investigation of used materials is needed to put objects produced by forced labour in historical context. In this study, we analysed signposts from the Auschwitz-Birkenau State Museum (Poland) collection to gain information about used materials, the object’s genesis as well as damage phenomenology. Literature research suggests that the signposts may be produced within the former German NAZI concentration and extermination camp. Inorganic constituents were identified using elemental analysis, such as X-ray fluorescence (XRF) and scanning electron microscopy coupled to an energy dispersive X-ray spectrometer (SEM–EDS). Organic matter was analysed utilizing vibrational spectroscopic instrumentation Fourier transform infrared spectroscopy (FTIR). Our results include the use of synthetic organic pigments (SOPs) and binders, which were newly emerged paint materials at that time. The study highlights the need for conservators to have detailed understanding of composite materials and demonstrates the need for further investigation concerning painted steel objects.