Dyes and Dyeing Methods in Late Iron Age Finland
This dissertation is about Late Iron Age (AD 800 1055/1300) woollen, visually colourful textile fragments. The aim is to identify the dyeing methods used in Finland during the Late Iron Age and to find the locally used dyestuffs. This dissertation focuses on the archaeological samples from inhumation burials and shipwrecks, which were analysed with visual analysis and microscopy observation. The reference material includes woollen yarns dyed with Finnish traditionally known dye sources. The archaeological samples and the dyed references were analysed chromatographically at the Cultural Heritage Agency of the Netherlands (RCE) and at the Royal Institute for Cultural Heritage (KIK IRPA) in Belgium by HPLC (High performance liquid chromatography) and UHPLC (Ultra High performance liquid chromatography) Mordants were analysed at the Nanomicroscopy Center of Aalto University in Finland by SEM EDX (Scanning electron microscopy with energy dispersive X ray spectroscopy) Experimental archaeology was used to reconstruct the actual dyeing methods of red tannins, lichen orchil and plant mordants as well as to test the sustainability of these dyes and the effect of dyeing methods on wool yarns. The results suggest that three different dyeing methods were used in Late Iron Age Finland: vat dyeing, mordant dyeing and fermentation of tannins. Red tannins were obtained from tree barks such as alder buckthorn (Rhamnus frangula) and roots of common tormentil (Potentilla erecta) Red anthraquinones were obtained from local bedstraws (Galium boreale, Galium album and Galium verum) Mordants for dyes were prepared by fermenting clubmosses (Lycopodium species) and horsetails (Equisetum silvaticum and Equisetum arvense) Eagles fern (Pteridium aquilinum) common chickweed (Stellaria media) and red sorrel (Rumex acetosella) were also used in mordanting. Woad (Isatis tinctoria) was used for blue dyeing. Purple was obtained from orchil producing lichens such as rock tripe (Lasallia pustulata) Dyer s madder (Rubia tinctorum) and the yellow flavonoid dyes such as weld (Reseda luteola) were interpreted to indicate textile import. The Middle Ages offered new meanings for life and textile making, new handicraft methods and new dyestuffs, which ended the local prehistoric dyeing tradition. As a result of new cultural influences, red tannins were no longer used to strengthen yarns for warp weighted loom nor were the blackish blue and purple textiles dyed in vats in the Late Iron Age manner. The medieval culture provided a faster textile making process and offered horizontal looms and spinning wheels, the boiling method, alum and new dyestuffs.%Vaitoskirja kasittelee villaisia ja visuaalisesti varillisia rautakauden lopulle (800 1055/1300 jKr. ajoittuvia tekstiilifragmentteja. Tavoitteena on tunnistaa variaineet ja varjaysmenetelmat, joita kaytettiin Suomessa rautakauden lopulla. Tarkastelun kohteena on arkeologisia tekstiilijaanteita ruumishaudoista ja laivojen hylyista. Loytojen rakenne analysoitiin visuaalisesti ja mikroskopian.