Analytical imaging and spectroscopy of wall polychromes in the saltworks castle in Wieliczka, Poland

A comprehensive spectroscopic and analytical imaging study of newly uncovered wall polychromes in the Wieliczka Salt Mine's castle reveals their historical significance, dating from the late 16th to the 19th century. These rare secular monumental paintings, featuring heraldic compositions linked to the Polish–Lithuanian Commonwealth and the House of Vasa, were analyzed using X-ray fluorescence (XRF), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR), and imaging in visible and ultraviolet light. The research identified historical pigments such as smalt, vermilion, red lead, lead-tin yellow, azurite, malachite, orpiment, carbon black, and secondary copper minerals, along with protein-based binders indicative of tempera or glue techniques. These findings provide critical insights into the material composition, stratigraphy, and technological practices of the polychromes, enhancing their art historical interpretation and guiding future conservation efforts.

Klisińska-Kopacz, A., Grajny-Brzezińska, P., Wilkosz, T., Obarzanowski, M., Ochniak-Dudek, K., & del Hoyo Meléndez, J. M. (2026). Analytical imaging and spectroscopy of wall polychromes in the saltworks castle in Wieliczka, Poland. Measurement: Digitalization, 8, 100061. https://doi.org/10.1016/j.meadig.2026.100061