Medieval Dyeing: Dye-stuffs

There is a mis-conception in some circles that medieval textile technology couldn't achieve the rich hues that the modern chemical dyes do. This misconception may in part be due to the loss of colour in many of the textiles that have survived, only after hundreds of years of exposure to light, humidity and in many case dirt. Given the conditions it is hardly surprising that such textiles are dull, washed-out or discoloured. However the medieval dyeing industry was fairly advanced and had at its disposal not only a host of dyestuffs that could easily be gathered just out the back door, but industrially grown and harvested dyestuffs that were traded all across the Eurasian 'continent' and beyond.

It is important to distinguish between the preferred dyestuffs that were commercially grown for the textile industry and went into the best goods, and the 'local' dyestuffs that might be used by the equivalent of cottage industry. It is also important to recognise that we are talking about a several hundred year period during which the technology advanced and new goods became available or more plentiful due to an increase in trade and others lost favour or were replaced.

Period dyestuffs

A number of the popular natural dyes used today were not available in period. However there are many that were. To find out what is an appropriate dyestuff for a particular colour you can go to several sources: Compleat Anachronist #41 is a catalogue of over 150 period dyes. An appendix in Textiles and Clothing c 1150 – c 1450 details the dyes found in the textiles discussed. There are discussions of dyeing in Tournaments Illuminated, many textile history books and academic papers that discuss early textiles. Some recipes have also survived.

Unfortunately the discovery of dyes by archaeological methods is complicated by the properties of the dyes, some of which break down more quickly than others, and some of which can be masked by the natures of the soil that the items are buried in. However the following dyes are among those confirmed:

Colour Dyestuff Source Period
Blue Woad Plant (leaves) All
Blue Indigo Plant (leaves) 15th C
Red Madder Plant (root) All
Red Brazilwood Plant (wood) 13th C
Red Kermes Insect All
Purple Orchil Lichen All
Purple Logwood Plant (wood) 16th C (New World)
Yellow Weld, dyers greenweed/broom, coreopsis, marigold, chamomile Plant (flowers/plant) All
Brown Walnut Plant (husks/leaves) All
Black Iron Metal All

Yellow

Yellows are difficult to identify – they can be found in huge range of plants but cannot always be determined by archaeological tests. Weld (Reseda luteola) is the most colourfast and was the preferred commercial yellow in the medieval period so is a good choice. Dyers broom / greenweed (Genista tinctoria) was widely used in the Coppergate finds. Marigold (Tagetes), dyers coreopsis and dyers chamomile are other alternatives.

Red

Madder (Rubia tinctorum) root was the preferred source of red dye in period. The bulk of materials analysed from the Coppergate site in York (which covers Roman to Renaissance finds) were dyed with madder. Madder is available, both as seed to grow your own, or as chopped or powdered roots ready for dyeing with.

The insect kermes (Quercus coccifera) was found in the Mediterranean and imported into England from the 13th century but is no longer available. It was used in the best textiles but was expensive. However a similar scale insect, cochineal, which was known in late period (after Cortés brought it back from Mexico in 1519), is widely available for hobby dyers and many believe that it is an acceptable alternative.

Brazilwood was available from the mid 13th century in Europe and came from the East. The South American country Brazil was named for the Brazilwood varieties found there, not the other way around. It is available as chips or sawdust from craft shops.

Blue

In the medieval period blue was derived exclusively from the leaves of the plant woad (Isatis tinctoria). To extract the blue dye involves a fairly involved process of fermentation and de-oxygenation and woad was exported, semi-processes, all around Europe. Indigo became popular in the 16th century but was often legislated against in order to protect the national woad industry and woad remained the chief source of blue until the 17th century.

Purple

Purples can of course be derived from using red and blue dyes together. Lichen dyes made a significant portion of the dyed material from Coppergate and many similar purples are gained from a wide range lichens.

Another source of purple is the wood Logwood which was introduced in the 16th century from the New World. It can make very deep purples but unfortunately is not terribly colourfast (it can actually rub off and deteriorates in the light) and so was legislated against as an inferior dyestuff.

Brown

Wool comes in its own range of browns but if brown was desired the black walnut hulls make a lovely brown. Tan colours can also be derived from earths such as ochre.

Black

True black is a notoriously difficult colour to achieve however this didn't mean that it was unusual, in fact black was popular. You can get a black by repeated over-dyeing and then post-mordanting in iron which 'saddens' the colour. Introducing iron into the dye process also has the effect of weakening the fibre so that black textiles very rarely survive the centuries.

Chemicals

The process of dyeing is essentially a chemical process, therefore dyeing is truly a science rather than an art, even if the science of it was not understood in period. Chemicals in the dyestuffs react with other chemicals introduced during the dyeing process and the material to be dyed to permanently colour the material. The following 'chemicals' were also used in the dyeing process.

The purpose of the mordant is to assist the dye in sticking to the material and improving its permanence, both in terms of colourfastness and lightfastness.

The chief mordant in period was alum. Alum (aluminium) can be used either in the dyebath itself or as a pre-mordant. It generally brightens colours without really effecting the colour itself (some mordants alter the tone). It was mined from early times and was a valuable commodity. Too much alum can make wool sticky and it is often used with tartaric acid to assist with this. The Coppergate finds showed the use of Clubmoss which is high in alum as an alternative to mined alum.

Copper (blue vitriol) is another metal based mordant. It tends to add a blue/greenish cast to dyes. Simply dyeing in a copper pot may be enough to mordant the fibre.

Other chemicals used in dyeing processes:

Ammonia, in the form of stale urine, is a key ingredient in processing woad and is also used to shift the acidity levels and thereby alter colours in various dyes, for example madder.

Iron, as noted above, is used to sadden or darken colours, often as an after-bath.

Sources

These are the sources that I have used, no doubt there are others.

Rainbow of colours