Colors and dyeing methodsBlue, red, yellow, green, brown and black - the textile finds from Hallstatt display the colour diversity of prehistoric textiles. In Europe, Bronze Age and Iron Age textiles have rarely preserved their colours, and if they have in Hallstatt, it is due to the preservative effect of salt and of the constant climatic conditions in the mine. Thanks to special methods such as chromatographic analysis of dyes, experts have shown that complex dyeing techniques were already known in the Bronze Age and the Hallstatt Culture.
Yellow and red dyes
Brown and black dyes
Traces of vat dyes, direct dyes and mordant dyes in Bronze Age and Iron Age textiles from Hallstatt indicate that the following three important natural dyeing techniques were employed: vat dyeing, direct dyeing and mordant dyeing. Textiles often had to be dyed at least twice in order to achieve certain color shades. Microscopic analyses have shown that certain fabrics were dyed blue using woad after the spinning and weaving process had been completed. When dyeing individual yarns, the blue dye was often not able to penetrate the whole yarn; in piece dyeing, the threads on top meant it was not possible to achieve an even blue color. Therefore, dyeing textiles (particularly blue and black) was a time-consuming procedure. It can be assumed that blue and black clothes were popular at the time as they contrasted with polished jewelry made of bronze and iron.
Indigotine and indirubin are characteristic of dyeing processes carried out using the indigo plant. During the Bronze Age and Hallstatt Period in Europe woad would have been used. The discovery of a blue pigment contained in woad and the development of vat dyeing made it possible to dye fabrics blue. The blue indigotine - an organic pigment and vat dye insoluble in water - was transformed into an insoluble yellowish compound through reduction in a fermentation vat. Fleece, yarn or fabric dipped into the vat and then hung out to dry turned blue as the oxygen in the air oxidated the yellow solution to become blue indigotine. During the Hallstatt Period this blue woad dye was combined with tanning agents as well as yellow and red dyes in order to create subtle effects.
Soluble yellow and red dyes can be used on their own for dyeing, but permanent results are only possible with tanning agents or mordant dyes containing aluminum, copper or iron. While aluminum-based mordant dyes do not change the dye color, contact with copper and iron results in a darker shade - for example, yellow flavonoid dyes turn olive green when combined with copper and olive brown when combined with iron. These chemical elements either come from the solutions used in prehistoric times for dyeing or from the compacted mining debris (Heidengebirge). Aluminum and iron may have come from minerals; copper may have come from the tips of bronze picks which had broken off.
Many plants contain flavonoids which can be used for mordant dyeing of textiles. However, it is often difficult to determine which plants the dye came from since the same dye can often be found in several different plants. Analyses are made even more difficult by the fact that over the centuries the subsidiary coloring matters characteristic of each plant have been broken down in the dyed materials to a level that is no longer detectable. Dyes from Hallstatt containing luteolin and apigenin may have come from dyers rocket, dyers broom, yarrow or dandelion; those containing only apigenin would have come from scentless chamomile.
Unfortunately, the anthocyanins contained in red and blue blossom and fruits cannot be used to dye textiles. Only with the discovery of red anthraquinones did it become possible to dye fabrics red with a permanent effect. However, these mordant dyes which provide the best color fastness are only rarely found in the rhizomes of the rubiaceae plant family as well as certain insects. Analyses of the textiles found in Hallstatt have revealed that these dyes had been discovered and were in use by the Bronze and Iron Ages.
Traces of purpurin in a piece of textile which is now olive-colored prove that plants from the rubiaceae plant family (probably galium) were used in the Bronze Age to dye fabrics red. The discovery of orcein - a red dye that is not lightfast - indicates that during the Hallstatt Period orseille was extracted from lichen and used for dyeing. Textiles from the Hallstatt Period also contain an anthraquinone similar to red carminic acid. It is likely that this dye came from insects, with carminic acid being the main dyeing agent. The Polish cochineal lives in Northern Europe and the Armenian cochineal is to be found around Mount Ararat in Western Asia. The fact that these insects used for dyeing do not live in the region around Hallstatt indicates that either the insects themselves or the dyed fabrics must have been imported.
Chlorophyll contained in plants cannot be used for dyeing textiles. Even during the Hallstatt Period it was known that fabrics needed to be dyed twice in order to achieve a green color - first with woad blue vat dye and then with yellow mordant dye. Olive green textiles were originally dyed yellow. They then darkened after coming into contact with copper either in the mordant dye itself or as a result of the dyed textiles being stored near broken bronze pick heads down in the mines. Copper and iron contained in the mining debris of the Heidengebirge can also turn light, non-dyed wool shades of olive green and olive brown.
Tanning agents from tree bark, fruits and galls can be used on their own to dye textiles (direct dyeing). While such agents have not been found in brown textiles in Hallstatt, they have been detected in black textiles. Many of the brown Bronze Age textiles from Hallstatt were made using brown sheep´s wool. A large number of textile fragments from the Hallstatt Period have also been shown to contain traces of yellow dye. The brown color of these fabrics was created in prehistoric times by adding red and blue dyes as well as mordant dyes containing copper or iron. Alternatively, it is possible that the textiles turned brown as a result of being stored near copper and iron in the mines.
Analyses have shown that a combination of tanning agents and materials containing iron was used to create ferro-gallic dye used in the Bronze and Iron Ages to dye materials black. Particularly dark tones could be achieved by dyeing the material again with woad blue, yellow and/or red dyes.
(Hofmann-de Keijzer, R. Van Bommel, M. R. Joosten, I. Hartl, A. - Heiss, A. G.)