We have seen that from very early times (about 20,000 BC) clothing made of spun yarn had been used, in large part to communicate the identity and status of the wearer. There is indirect evidence of woven cloth (loom weights) dating to 5500 BC. Much of the appeal of woven cloth comes from the use of colored yarns to produce patterns in the weave. In order to survive repeated uses and washings, these colors must be fast, that is, they must not wash out with water.
Vegetable fibers, like flax, tend to be white or tan but few colorfast dyes were available in antiquity. Consequently, Egyptian linen (flax) textiles of the dynastic period (3000 BC - 1250 BC) were white in color. By about 4000 BC, sheep began to be domesticated increasingly for wool rather than meat. One advantage of wool over flax is that it comes in a varity of natural colors, from white to tan, to brown, grey, and black. Thus cloth woven from colored wool can exploit a variety of weaving patterns which would be almost invisible in uncolored linen.
The figure above shows wool from a variety of breeds. Even the most colorful
of these wools is relatively subdued. In antiquity, colored wools would have sold
at a premium and even today they are expensive relative to white wool.
The use of colored wool, then was a great advance in the ability of textiles to connote wealth and status. But the larger advance came as a consequence of the ease with which wool can be dyed. The first stains were probably accidental. Nuts and berries collected for food came in contact with clothing and stained them. Most of these colors washed out, particularly with soap and water. But some of the stains proved colorfast and over time plant materials were likely collected for dyeing rather than eating.
These wools have been dyed with a variety of colors from animal and vegetable sources. They are far more intense, yet less expensive than the naturally colored wools.
A second advance came with the discovery that wool could be treated in order to enhance the colorfastness of a wide variety of vegetable dyes. First of all, removing the grease from the wool by washing with soap improves the ability of the wool to absorb dyes. Second, certain minerals can cause dyes which normally wash out to withstand repeated washings. Such a material is called a mordant. Potash or soda ash acts as a mordant for some dyes and would have been readily available to any culture that was already producing soap. But soda ash is rather harsh and causes wool to become brittle.
The most popular mordants of all times is alum, potassium aluminum sulfate (KAl(SO4)2). Not only is this more gentle than soda ash, it works with a wider variety of dyestuffs. In ancient times it was mined and constituted a strategic mineral resource. A kingdom which could control the alum trade could wield considerable power.
Not all colors are equally available. Many substances will dye wool various shades of brown, tan, and buff. Fewer dyes are available for reds and yellows and still fewer for blues and greens. Purple was the rarest of all. Tyrian Purple was extracted by the Tyrians from a local shellfish. 8500 shellfish were needed to produce 1 gram of dye, making this a color to be afforded only by kings and princes.
Some dyes tend to fade over time while others remain vibrant for a long period. A dye that does not fade is called lightfast. One of the most popular dyes of all times, indigo, is not particularly lightfast. You are familiar with this dye as it is the blue in blue jeans. As you know, bluei jeans fade over time. This has been a disadvantage of indigo for millenia. In the sixties, faded blue jeans became an icon of the counter-culture. This has become mainstream fashion to such an extent that jeans are now often sold "pre-faded." Go figure.
As you can imagine, there has been continuing pressure over the millenia for new
and improved dyestuffs: brighter colors, greater colorfastness, and applicability
to a greater variety of different fibers. Up until the mid nineteenth century
all dyes were extracted from animal or vegetable sources. In the late nineteenth
century the first synthetic dyes began to be manufactured from coal and petroleum
sources. At first these synthetic dyes were of poorer quality than their natural
counterparts. Over time, however, the synthetic dyes steadily improved to the point
that today they have surpassed the natural dyes in the range and vibrancy of colors
available.
You may have wondered why we have spent so much time talking about textiles in a chemistry class. The drive for better and brighter synthestic dyes was in large part responsible for the rise of large-scale chemical manufacturing. Out of this dye industry, pharmaceuticals and photographic chemicals spun off. Finally, fibers such as nylon and polyesters began to be produced synthetically from petroleum. Thus a large part of the chemical industry originated from the drive for brighter, more colorful, more durable, and cheaper textiles.
These wools have been dyed with a variety of synthetic dyes (i.e. those derived
from petroleum sources).
Pokeberries grow wild on campus as well. They form unruly thickets with red berries that ripen in late September and early October. There is a large thicket within 100 yard of Gilmer Hall. You will need half a dozen "heads" of berries.
You can choose to use either or both dyes in this project. Black walnut does not require a mordant, while pokeberry requires a mordant in order to remain colorfast. We will use soda ash as a mordant. You may work with a group of other class members to collect and process the dyes, but each individual must dye his own piece of yarn. This project does not require sophisticated equipment. A pot and a stove are all that is needed, so it could be done in a kitchen. Do not boil soda ash in an aluminum pot: hot alkalis will eat through aluminum. If you don't have a kitchen, you may use the lab during the V period only.
Whichever dye you choose, your wool must be free of grease. Wash your homespun yarn thoroughly with soap and water. In most cases, a failed dye project can be attributed to insufficient washing of the wool prior to dyeing. If you have completed the soap project, your homemade soap would be perfect for this task.
Cut the rind from six black walnuts and place them in a beaker. Add just enough water to cover the rinds. Place your yarn into this water and put it on a hotplate. Boil the mixture until it turns dark brown. Remove the yarn from the water and put it, still wet with hot dye, into a plastic bag. Put your name on the bag and take it home to "stew in its juices" overnight. The yarn will get darker the longer it sits in the dye. When done, set it out to air dry. To test the colorfastness, wash it thoroughly with soap and water.
Throw your rinds and walnuts in the trash and pour your dye down the drain
when you are finished. Wash any and all utensils with soap and water and leave
the lab or kitchen area cleaner than when you found it.
Here are some handspun woolen yarns. The yarn on the left has been spun
in the grease, i.e., unwashed with the natural oils still on the fibers.
The yarn in the center was spun in the grease and then washed with lye soap.
The yarn on the right was spun in the grease, washed with lye soap, dyed with
black walnuts, and then washed again in lye soap. Notice that the color did
not wash out. Black walnut dye is both colorfast and lightfast.
Pokeberry makes an intense red dye. It is the original "garnet" of the Hampden-Sydney school colors. Without a mordant, however, pokeberry is not colorfast. We will use sodium carbonate (soda ash, washing soda) as a mordant.
Pick the berries from about half a dozen "heads" and place them in a pot or beaker with 250 mL of water. Make sure the berries are crushed, so that the juice colors the water. Heat the juice on a hotplate until it is hot to the touch, but not boiling. Boiling the juice will destroy the color.
Add 2 tbsp of washing soda to 250 mL of water in an iron pot or glass beaker and bring this to a boil. Immerse the wet yarn in the boiling soda solution until it turns from white to yellow. If you boil it too long, the wool will turn brittle. If your don't boil long enough, the dye will not be colorfast. Remove the yarn from the soda but do not rinse it out. Place your yarn in the hot pokeberry juice for 30 minutes. Remove the yarn from the juice and place it in a plastic bag to "stew in its juices" overnight. Then set it out to dry. You should find that the color does not wash out, even with soap and water.
Throw your berries and stems in the trash and pour your dye down the drain
when you are finished. Wash any and all utensils with soap and water and leave
the lab or kitchen area cleaner than when you found it.
Here are some more handspun woolen yarns. The yarn on the left has been spun
in the grease.
The next yarn was spun in the grease and then washed with lye soap.
The next yarn was spun in the grease, washed with lye soap, dyed with
pokeberry, and then washed again in lye soap. Notice that the color did
wash out. The yarn on the right was spun in the grease, washed with lye soap,
mordanted with washing soda, dyed with
pokeberry, and then washed again in lye soap. Notice that this time, the color
did not wash out. Properly mordanted, pokeberry dye is
colorfast but not lightfast.
Your woolen yarn should be dyed with a plant or animal material you collected and processed yourself. I have suggested black walnuts and pokeberries, but you may try other nuts or berries. The Weaving, Spinning, and Dyeing Book on reserve in the library has detailed instructions for many dyes. Some possibilities include:
| source | mordant | color |
|---|---|---|
| beets | alum | gold |
| tea | alum | rose tan |
| onions | alum | burnt orange |
| hickory | none | brown |
| pecan | none | brown |