Identification of dyes in Egyptian textiles of the first millennium ad from the collection Fill-Trevisiol

Abstract

High-performance liquid chromatography coupled to a diode-array detector (HPLC-DAD) is used to investigate 30 samples which were removed from 27 ancient Egyptian fabrics of the Fill-Trevisiol collection. Attention is focused in this paper on fabrics of the Roman and Byzantine periods, with red and deep violet–blue wool weft threads which are Z-spun. The following dyes are identified in fabrics which date to the Roman period (first–fifth c. ad): mollusc purple, madder, and indigo/woad (Indigofera species and other, Isatis tinctoria L.). The results for the Byzantine (fifth–seventh c. ad) fabrics are richer in terms of identified dyes: apart from the three aforementioned dyes, the use of kermes (Kermes vermilio Planchon) and cochineal is revealed as the two coccid dyes have been detected in six Egyptian–Byzantine fabrics. Moreover, a yellow dye (probably Reseda luteola L.) is identified in one sample. Finally, samples taken from two fabrics, which date to the Islamic period, were dyed using indigo/woad and lac (Kerria lacca, Kerr). Mixing madder and indigo/woad to imitate true purple was a common practice in ancient Egypt and this is confirmed by the HPLC results in several samples. Semi-quantitative results are obtained from the HPLC peak areas and lead to the following conclusions. Madder dyes which were rich or poor in alizarin, compared to purpurin, and could have been therefore obtained from Rubia tinctorum L. and Rubia peregrina L., respectively are detected in Byzantine fabrics. Only alizarin-rich madder dyes are identified in some samples from Roman fabrics, but in some other samples the relative alizarin-to-purpurin ratio cannot be measured with confidence. Cochineal is found in two samples. The biological source of cochineal (Porphyrophora hamelii Brandt) is possible to be chemically identified only in one sample. The HPLC results of the molluscan dye detected in a Roman fabric are compared with the relative compositions of extracts of the three Mediterranean molluscs leading to the speculation that the Roman purple sample was probably dyed using Hexaplex trunculus L. The molluscan dye was furthermore detected in a Byzantine sample where it was combined with madder. Finally, it is reported that the standard (hydrochloric) acid hydrolysis method which is commonly applied to extract dyes from archaeological samples does not have any noticeable effect on the relative composition of the molluscan dye.