Painting and dyeing ancient techniques of molluscan purple revealed by FTIR imaging and HPLC

Zoi Eirini Papliaka, Alexandros Konstantas, Ioannis Karapanagiotis, Recep Karadag, Ali Akin Akyol, Dimitrios Mantzouris & Panagiotis Tsiamyrtzis

Archaeological Anthropological Sciences, DOI 10.1007/s12520-015-0270-3, 26 July 2015

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Abstract

Fourier transform infrared spectroscopy and imaging coupled to optical microscopy, scanning electron microscopy coupled to energy-dispersive x-ray spectroscopy and high-performance liquid chromatography (HPLC) coupled to diode-array detection are used to investigate two samples removed from a painted decoration of a burial kline and a textile fragment, both found in Koru tumulus (fifth century BCE) in Daskyleion. `

Tyrian purple and kaolinite were identified in both samples, thus suggesting that the aluminosilicate compound had an important role in the applied painting and dyeing processes. The textile fragment is composed of undyed cotton and silk yarns dyed with the molluskan dye. The relative compositions of the molluskan materials used in the two archaeological objects are similar and comparable with the corresponding composition measured for a purple sample originated from Murex trunculus mollusks according to the HPLC results. This result is supported by principal component analysis (PCA) which, furthermore, takes into account the relative compositions of the extracts of the three Mediterranean mollusks, published in previous reports.

Conclusions

Kaolinite should have been included in the painting and dyeing recipes of Tyrian purple of the fifth century BCE. This conclusion was reached as the molluskan purple and kaolinite were found to co-exist (micro-FTIR, SEM-EDX) in a painted decoration of a burial kline and a textile fragment, both found in the Koru tumulus in Daskyleion.

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The results of Fourier transform infrared imaging (FTIRI) suggest that probably the treatment of the textiles fibers with kaolinite constituted a different stage, which might prelude the dyeing process with Tyrian purple. The textile fragment is composed of undyed cotton and silk yarns dyed with the molluscan dye.

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The relative compositions of the molluskan materials used in the two archaeological objects are similar according to the HPLC results, which were interpreted using principal component analysis (PCA) taking into account the relative compositions of the extracts of the three Mediterranean mollusks, published in previous reports. It is shown that the PCA scores calculated for the two archaeological samples are close to the corresponding data obtained for M. trunculus mollusks.