Raman microspectroscopy and SEM/EDS in the investigation of white and red painting layers from Celtic pottery from a Modlniczka site in Poland

Red and white painting layers from Celtic pottery from Southern Poland (Modlniczka 2 site near Kraków) were investigated with the use of Raman microspectroscopy, SEM/EDS and optical microscopy. The painting layers were performed homogeneously for all the examined shards, i.e. red layers as thinner, ca. 0,02 mm and white of 0,04 mm. The white painting layers are very fine grained and amorphous under SEM, prepared of compositionally complex magnesium based raw material, with phosphates and fluorite probably used as fluxes. Unusual phases: fluorite and silicon were identified. Raman spectroscopy of fine grained red painting layers revealed the presence of hematite and anatase/leucoxen. Again, rare phases, of silicon and destinezite were found. Both paints were carefully manufactured by grinding and homogenizing the raw materials. Their preliminary firing cannot be excluded. The painted pottery was fired approx. at 700–900 °C, but multistage firing is possible.