Ilon Gábor: Százszorszépek. Emberábrázolás az őskori Nyugat-Magyrországon (Szombathely, 2007)

Katalógus - Középső rézkor: Tőzdelt barázdás kerámia kultúrája - Mihály J.–Komlósi V.–Mink J.–Tóth A.–Tóth Zs.–Ilon G.: A Szombathely–Oladi plató ásatásból származó festékanyagok és festett kerámiák rezgési spektroszkópiai vizsgálata

Vibrational spectroscopic study of pigment raw materials and painted ceramics excavated at Szombathely-Oladi plató, Hungary ABSTRACT Infrared (FTIR) and Raman (FT-Raman) spectroscopic investigations were performed on raw pigment materials and painted ceramic fragments from the excavation of Szombathely-Oladi plató. In the raw yellow and red pigments we can identify limonite and hematite as colouring minerals, respectively. A special raw red pigment was found to be of purified hematite. On the ceramic fragments decorated with red, the paint layer proved to be made of cinnabar (HgS) mixed with high-purity kaolin. INTRODUCTION The excavations in 2006-2007 in Szombathely-Oladi plató, Western Hungary revealed a Late Neolithic, Early Lengyel Culture settlement excavated by Gábor Ilon (Savaria Museum, Szombathely, County Vas). On the excavated 3 hectar area several hundreds of features represent the Lengyel Culture. Most of them are pits belonging to the settlement, but some are special features (No. 1, 184 and 370), probably associated with cultic activities. The early period of the Lengyel culture is characterised by polichrom painted (red, yellow and white) pottery, as we can see in the already excavated settlements of Sé-Malomi dűlő and Gór-Kápolnadomb (Tóth 2006). Large amounts of painted pottery and fragments of pigments were found on the site demanding the identification of the minerals in the pigments and their possible binding materials. The painted decoration was widely used on the everyday pottery, as well as on the special objects, like figurines, altars, and lamps. Infrared and Raman spectroscopy, through their characteristic vibrational frequencies, provide information on both organic and inorganic components, usually present as heterogeneous mixtures in artworks and archaeological finds. Raman spectroscopy (totally non-destructive, non-invasive technique, with no sample preparation requirement) and FTIR microscopy (non-destructive or micro-destructive method) due to their high selectivity offer good sensitivity and high spatial resolution. As a result these methods are some of the most powerful tools in pigment identification (Casadio et al. 2001; Derrick 1995; Smith & Clark 2004). FT-RAMAN STUDY OF PIGMENT RAW MATERIALS The so-caüed earth pigments were used as polychrome pigments in this period. Red, yellow or brown pigments are decomposition products of iron oxide minerals, which by firing gained a deeper red hue (red and yellow ochre). Figure 1 shows the FT-Raman spectrum of a raw yellow pigment. Based on the spectrum limonite ((Fe203'H20) (696, 553, 398, 297, 255 and 242 cm"

1

) (Bikiaris et al. 2000), a-quartz (462, 199 and 124 cm"

1

) and anatase (396 and 144 cm"

1

) (Bordignon et al. 2007) were identified. From elementary SEM microanalysis it was established that beside iron (~4 mass%), high amounts of Al (7,57 mass%) and Si (36,54 mass%) are present, presumably in the form of aluminosilicates (kaolin). The presence of kaolin was also affirmed by the Raman bands of ccquartz and anatase (ТЮ2), both are typical impurities for kaolin. FT-Raman measurements on a special red pigment (Pict.l) revealed a purified hematite. In the Raman spectrum (Fig. 2) beside the well-defined hematite bands at 608, 495, 406, 290, 244, 221 cm"

1

, the medium intense band at 654 cm"

1 belongs to magnetite (FeßO^ (Bordignon et al. 2007). Alternatively, this band can be attributed to disorder effects in the crystalline structure (Bikiaris et al. 2000). The absence of a-quartz and anatase bands from the spectra indicates that the fragment may be the result of a purifying process indicating a purposeful preparation of the raw material. STUDY OF PAINTED POTTERY FRAGMENTS Preliminary SEM microanalysis revealed the presence of mercury in the red pigment on the examined ceramics (Pict. 2). FT-Raman measurements unambiguously identify the red pigment as cinnabar (HgS) (Fig. 3.). The use of cinnabar for ceramics decoration is quite unusual in this archaeological period throughout the whole