NB: This write-up is one section of a longer piece of documentation written for an upcoming A&S competition.
A number of natural dyestuffs were known and used in northern Europe during the Viking Age, principal among them madder, weld and woad. These would have been used along with mordants such as alum, iron, copper and tannin to produce a wide range of bright colors on wool, linen and silk.
Madder was the most commonly identified dye plant found in the Coppergate digs, and the most commonly identified dye found on textiles in the same area and might easily have been grown in the vicinity. Madder does require a mordant in order to adhere to fibers. While alum would have been difficult to find in England during the period, Walton argues that large quantities of imported clubmoss found in the area were probably used as an alum substitute. There is also evidence of iron having been used as a mordant on the caps found in Dublin. Copper and tannin were also used as mordants during the period.
Wool could have been dyed at any stage during processing, either as unspun fleece, yarn, or finished fabric. Fulling was not commonly used as a finishing technique until the medieval period (see Walton), so it is likely that most dyeing was done prior to weaving as the dye bath tends to continue the fulling process and most extant textiles from the Anglo-Scandinavian digs do not have a compacted, fulled appearance.
Not all cloth during the period would have been dyed. Wool comes naturally off the sheep in a wide range of colors, and many textiles from natural wool colors have been found. As seen on the Dublin caps and discussed above, not all caps were dyed, but colored caps were not unknown. In addition, utilizing the natural colors of wool in combination with dyes can produce a broader range of possible colors, Walton points to one textile from Anglo-Scandinavian York which had proved to be grey wool dyed with madder.
For my cap, the finished cloth was dyed using madder with an alum mordant. I elected to use alum as it is safer and easier to use than iron, and was was used in conjunction with madder during the period. The fulled cloth was wetted and soaked overnight. I then dissolved 4 ½ tsp cream of tartar and 4 ½ tsp alum in boiling water, added this to cool water in my dye pot and added the cloth. The mordant bath was heated slowly to simmering, and held there for an hour. The cloth cooled in the alum solution over night.
While my fibers were in the mordant bath, I prepared my dyestuff. I used 4 ounces of madder root, and chopped it roughly and set it to soak overnight. I removed the wool from the mordant, filled my dye pot with clean water and added the soaked madder root and liquid. I then replaced the wool, and gently heated the dye pot, taking care not to overheat the dye as this can result in duller shades. I stirred the pot occasionally and after a day was able to exhaust the bath and produce a bright reddish-orange cloth.
According to all of the sources on madder dyeing I had consulted, the roots needed to be soaked overnight prior to dyeing. Unfortunately, all I was able to find to put the roots in was a plastic pickle jar. Knowing that vinegar is an acid and that acid is a modifier which will significantly change the color natural dyestuffs, I took care to wash the jar thoroughly before soaking my roots. The next day I carried on my dyeing, but noticed after about an hour that my wool was turning a brilliant shade of reddish orange rather than a clear red. After soaking the wool for a day in a warm bath, the result was the exact color my dye book said I would get if I followed an alum mordant with an acid modifier, rather than the clear red I had intended. Apparently the plastic had retained just enough acetic acid to alter the color of my dye bath.
Sources:
Crowfoot, Elisabeth. Textiles and Clothing c.1150-c.1450. Medieval Finds from Excavations in London, 4. London: Her Majesty's Stationery Office, 1992
Walton, Penelope. The Archaeology of York: The Small Finds Textile Production at 16-22 Coppergate. The York Archaeological Trust, 1997.
Lead, Drea. Dye Recipes from The Innsbruck Manuscript c.1330 (http://www.elizabethancostume.net/dyes/innsbruck/) Last visited January 18, 2011.
Dean, Jenny. Wild Color. Watson-Guptill Publications, 1999.
Priest-Dorman, Carolyn. Colors, Dyestuffs, and Mordants of the Viking Age: An Introduction
(http://www.cs.vassar.edu/~capriest/vikdyes.html) Last visited Nov. 18, 2010.
Mckenna, Nancy. Madder dyeing. Medieval Textiles issue 29. Sept. 2001. (http://www.elizabethancostume.net/dyes/medtex.pdf) Last visited Nov. 18, 2010
Leed, Drea. A Lytel Dye Book (http://www.elizabethancostume.net/dyes/lyteldyebook/index.html) Last visited January 18, 2011.
