A novel piece of Minoan art in Italy: the first spectroscopic study of the wall paintings from Phaistos

Some fragments of wall paintings of Phaistos (Crete), belonging to the Bronze Age, from the Archaeological National Museum of Florence, were analysed to investigate the material composition of their pictorial layers and to explore the pictorial technology. These samples belong to the oldest surviving examples of decorative polychrome painting on plaster from Crete and constitute a further document in the frame of the already known evidences of painted materials from the palatial sites. The wall painting fragments were studied to define the composition of the paint layers and of the plaster used as substrate, and to classify the painting method. The coloured strata were investigated through micro-Raman analyses by acquiring the vibrational spectra on different points selected for every hue, whereas for the plaster, different techniques were employed such as optical microscopy, X-ray diffraction and Fourier transform infrared spectroscopy. In accordance with similar Aegean Bronze painted plasters, the obtained results show a rather homogenous colour palette mostly made of mineral pigments, which recur in the different tones in all the fragments. The absence of organic binders and the possibility to differentiate calcite grains present in the painting layers from that present in the plaster underneath were indicative of fresco-secco technique. On the whole, the obtained results could be considered as valuable archaeological indicators for the contribution they could offer to the comprehension of the painting techniques and the materials used in Crete during the Medium Minoan period.