Detection and identification of dyes on Anglo-Scandinavian textiles

Some of the dyes that may have been used in Anglo-Scandinavian York are listed. Procedures for extracting dyesfrom textile samples are described. Identification of dyes is based on comparison of the visible spectrum withthose of known dyes. Addition of magnesium acetate to a solution in methanol of many of the mordant dyes causes a characteristic change in the absorption spectrum which enhances the sensitivity of the detection, and can be used to strengthen the identification of the dye. Because of spectroscopic interference from staining extracted from the textile along with the dye, yellow dyes cannot be reliably identified without separation of dye from dirt. The extraction procedures described are not, in general, applicable to lichen dyes. Of over 90 Anglo-Scandinavian textile samples investigated, over one half show evidence of having been dyed, and on about onequarter of the samples, madder and indigotin were positively identified. The madder was Rubia tinctorum L. Yellow dyes, and probably most lichen dyes, would not have been detected.