The "Coptic" textiles of the "Museo Egizio" in Torino (Italy): a focus on dyes through a multi-technique approach

The Coptic textile collection of the Museo Egizio in Torino (Italy) has been the object of a broad project aimed at investigating the production techniques, at documenting the conservation state and at reconsidering the attributed age. The collection was also analysed by non-invasive and microinvasive techniques with the aim of detecting the dyes that have been employed to obtain the colours, in order to complete the set of technological information available for each textile. The data collected in the present work have been compared with published results from other Coptic textile collections, with the aim of highlighting a possible link between the age of the textile and the dyes that were employed. Moreover, the combined use of spectroscopic and chromatographic techniques allowed us to compare the results for the non-invasive and the micro-invasive approaches and to go deeper into the dyeing technology by detecting unexpected combinations of dyes. In particular, the use of a double dyeing with madder and Indian lac dye was revealed in some Roman-Byzantine and Byzantine textiles from the collection.