The unprecedented identification of Safflower dyestuff in a 16th century tapestry through the application of a new reliable diagnostic procedure

A set of samples collected from two 16th century silk tapestries belonging to Quirinale Palace in Rome and presently under restoration at the Opificio delle Pietre Dure (Florence, Italy) was investigated in order to disclose the nature of the dyes employed in their production. The identification of the colouring materials was achieved through the application of an optimised reliable procedure, based on dimethylsulfoxide extraction of the dyes from the yarns followed by a hydrolysis treatment in an acidic methanolic solution with hydrochloric acid; the extract is then analysed by high performance liquid chromatography with diode array detector (DAD). This study has lead to the identification of a wide range of colours; expensive dyes were used to dye the analysed silk yarns: coccid dyestuffs, madder, weld, young fustic, tannins and an indigoid dye were identified. Moreover, the use of safflower has been assessed for the first time in a European fabric.