Abstract Detail

Poster Session

Hartl, Anna [1], ProaƱo Gaibor, Art Ness [2], van Bommel, Maarten R. [3], Hofmann-de Keijzer, Regina [4].

More than blue?! Surprises during dyeing experiments with woad (Isatis tinctoria L.) and an explanation through dye analysis.

In Europe, woad was used for millennia to dye blue. The earliest woad-dyed textiles in Europe to date have been found in the salt mine in Hallstatt, Austria. They are up to 3500 years old, dating from the Bronze Age (1500–1100 BC) and Iron Age (850–350 BC). In these textiles, indigotin, indirubin and isatin were detected by high-performance liquid chromatography with photo diode array detection (HPLC-PDA). These components clearly indicate vat dyeing, but do not enable a conclusion which plant species yielding indigoids the people of the Hallstatt Culture used. Due to the textiles’ prehistoric context, it was most probably woad. The starting point for the research presented here was the requirement to produce replicas of these textiles. Three processing and dyeing methods using woad (Isatis tinctoria L.) were successfully recreated in an iterative experimental process, based on ethnographic, historical and experimental literature: (1) dyeing with fresh leaves, (2) dyeing with green and couched woad, and (3) dyeing with woad pigment in urine vats and madder-bran-vats. During these experiments, several colours other than the typical blue also emerged. Dye analysis using HPLC-PDA showed that the most predominant component in the blue samples was indigotin. The colours mint, purple, beige and green were achieved when indirubin and flavonoids appeared in higher concentrations. The composition of the woad-related components detected on dyed samples enabled us to retrace the dyeing methods used. Antraquinones originating from madder (Rubia tinctorum L.) used in the madder-bran vat were also detected, but in different ratios to that of madder mordant dyeings. Further research is required to prove whether the components detected in reference samples can be used to identify dyeings with woad or the use of madder-bran vats in prehistoric and historic textiles.

1 - University of Natural Resources and Life Sciences Vienna, Division of Organic Farming, Department of Sustainable Agricultural Systems, Gregor-Mendel-Strasse 33, Vienna, A-1180, Austria
2 - Cultural Heritage Agency of the Netherlands, Sector Knowledge Moveable Heritage, Hobbemastraat 22, Amsterdam, 1071 ZC, The Netherlands
3 - University of Amsterdam, Faculty of Humanities and FNWI, Conservation and Restoration of Cultural Heritage / HIMS, Johannes Vermeerplein 1, Amsterdam, 1071 DV, The Netherlands
4 - University of Applied Arts Vienna, Department of Archaeometry, Salzgries 14, Vienna, A-1010 , Austria

woad (Isatis tinctoria L.)
natural dye
dye analysis
fermentation vat.

Presentation Type: Poster
Abstract ID:86
Candidate for Awards:None