There is a misconception 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 color 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 discolored. 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 recognize 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 favor 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 color you can go to several sources: Complete 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:
| Color | Dyestuff | Source | Period |
| Blue | Woad | Plant (leaves) | All |
| Blue | Indigo | Plant (leaves) | 15th C |
| Red | Madder | Plant (root) | All |
| Red | Brazil wood | 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 colorfast 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 analyzed 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.
Brazil wood was available from the mid 13th century in Europe and came from
the East. The South American country Brazil was named for the Brazil wood
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 colorfast (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 colors can also be derived from earths
such as ochre.
Black
True black is a notoriously difficult color 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
color.
Introducing iron into the dye process also has the effect of weakening the fiber
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 color 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 colorfastness and light fastness.
The chief mordant in period was alum. Alum (aluminum) can
be used either in the dye bath itself or as a pre-mordant. It generally brightens
colors without really effecting the color 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 Club moss 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 fiber.
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
colors in various dyes, for example madder.
Iron, as noted above, is used to sadden or darken colors,
often as an after-bath.
Sources
These are the sources that I have used, no doubt there are others.
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