Tutankhamun’s polychrome wooden shawabtis. Preliminary investigation for pigments and gilding characterization and indirect dating of previous restorations by the combined use of imaging and spectroscopic techniques

To the best of our knowledge, such a detailed study on polychrome wooden shawabtis of King Tutankhamun (18th Dynasty in ancient Egypt) has not been reported in the literature, so the purpose of our study is to noninvasively identify the polychrome layers and previously applied materials for a number of wooden shawabtis that belong to King Tutankhamun through a protocol based on imaging techniques integrated with single-spot spectroscopic techniques. In the first step, imaging techniques (visible, ultraviolet induced visible luminescence, ultraviolet reflected, visible-induced infrared luminescence, infrared reflected, and infrared false color) and optical microscopy were applied to gather information and provide evidence on the distribution of original and previously applied materials on the polychrome surfaces. In the second step of our work, we analyzed the selected areas with single-spot analyses (handheld X-ray fluorescence spectroscopy and visible reflectance spectroscopy) and X-ray diffraction analysis. The materials of the previous restoration interventions were studied by Fourier transform infrared spectroscopy. The application of a protocol based on imaging techniques integrated with data obtained from single-spot spectroscopic techniques allowed the characterization of a remarkable number of polychrome layers and some previous restoration materials and mapping of their distribution on the original surface, which provides not only essential data for the follow-up treatment and conservation works but also offers important information for the study of polychrome wooden shawabtis of other periods in ancient Egypt.