Servizio Comunitario di Informazione in materia di Ricerca e Sviluppo - CORDIS

Flavonoid and neoflavonoid dye identifications for historical tapestry samples

From the outcomes of 2 and 3 above, the PDA HPLC analysis of 245 yellow, orange and green historic tapestry yarns revealed weld and DGW in 115 samples of wool and 59 samples of silk. Weld was found to be the principle dye for wool as a single colour source and in combination with other dyes. Re-evaluation of the weld identification after the accelerated ageing study of weld and sawwort indicated that sawwort had not been used. By contrast, DGW was predominant as a dye for silk. Dye sources for the remaining 71 samples could not be identified for several reasons: limited sample size; unknown flavonoid profile; or simply because the yarn was undyed.

Logwood was identified in three black historical yarns and brazilwood in sixteen yarns by PDA HPLC using the marker compounds resulting from the acid hydolysis extraction of the neoflavonoids hematein and brasilein respectively. PDA HPLC analysis of the silk cores from nine historical metal threads revealed that young fustic was the dye of choice, used with and without weld and brazilwood.

An important and necessary aspect of the project was re-evaluation of the historical sample results when new information emerged from parallel UoE research for minor dye component characterisation, and light ageing and analysis effects on the chemical compositions of the dyes.

Results from other workpackages (deliverables 9 and 11) indicate that the dyeing process for flavonoid yellow dye sources influences the strength properties of aged fibres. Because the dyeing process is typically dependent on the dye, accurate identification of the original source becomes an important aspect of tapestry damage assessment. Dye identification also relates to materials selection, e.g. choice of dye source, which are certain to reflect availability as well as regional and period preferences. The results for the well-dated and provenanced tapestries studied provide context, which is relevant not just for tapestries but a wider range of historical textiles.

Informazioni correlate

Reported by

National Museums of Scotland
Royal Museum of Scotland Chambers Street
EH1 1JF Edinburgh
United Kingdom
See on map