Rowan's Woad Page

Woad Page Directory

This is a page devoted to the Woad plant, Isatis tinctoria, an easily cultivated source of blue dye. I have not studied it as much as I would like to but as time allows more will be added to this page. The pull-down menu above will help to get around the page and click on any "" to get back to it.
Last Updated: December 2, 2006

My interest in woad began with hearing tales about the ancient Picts who painted Celtic designs on themselves with a woad body paint for magical protection in battle. While I have discovered these beliefs to have little historical accuracy, my interest in the plant and it's lore, historic and modern, has not diminished at all.

Woad, Isatis tinctoria, is a hardy biennial plant native to northern Europe and the British Isles that is a source of the blue dye chemical, indigotin, that is also produced by the much stronger and more famous sub-tropical indigo plant. While much weaker than indigo, woad can be a good source of dye to the modern dyer.
I have found woad to be very easy to grow and a big crop is not the difficult to achieve if you grow a row of it. Its first year is when most leaves are harvested for dyeing and in its second year when woad is in flower as in the photo above, it's very pretty and it will produce a huge quantity of seeds as seen at the left. It loves full sun and has done well in every soil that I have tried to grow it in. Because it self-seeds so aggressively it had gained a bad reputation with many agricultural groups.
Preparing the dye and dyeing with woad are both complicated processes, more that most other natural dyes. The dye is extracted from the plant by a wide variety of techniques, but causing a chemically oxidizing reaction in an alkaline environment is required. Once the dye is oxidized and often concentrated it is returned to an alkaline solution and chemically reduced to dye fibers or leather. For all that effort woad can produce a long-lasting blue.
Woad started out as the source of much of blue dyes in northern Europe because the stronger indigo is difficult to grow in most northern climates, but as shipping increased, woad soon fell by the wayside as more tropically grown indigo took over the market. Information on woad can be found on its own page in the excellent "modern herbal" Botanical.com
My interest in woad began with hearing tales about the ancient Picts who painted Celtic designs on themselves with a woad body paint for magical protection in battle. While I have discovered these beliefs to have little historical accuracy, my interest in the plant and it's lore, historic and modern, has not diminished at all.

Growing Woad

Caution: Woad aggressively self-seeds and can become a pest problem.

Woad is very easy to grow in sunny or partly sunny locations. As a biennial it grows one year, flowers and produces seed the second year and dies.
All above ground parts of the plant will produce indigotin, but in fairly small concentrations so be willing to plant as much as you have room for. The dye can be processed any time with any amount of plant material, but being a biennial, flowers are only produced the second year, but in tremendous abundance. To prevent woad from becoming a serious weed problem cut back all but one or two flower stalks and the remaining flowers will provide all the seeds you need for the next season.

Processing Woad

A bit of vocabulary first: "indigotin" is the blue dye, whether you get it from woad- Isatis tinctoria, true indigo- Indigofera tinctoria, or some other source. To process fresh woad into blue dye, you will need fresh woad plants, sparkling non-sudsy ammonia, an egg-beater, cooking whip, or electric mixer; some glass jars and a non-stick cooking pan. Be prepared for a small yield because woad contains only one tenth of the indigo that true indigo plants contain. I have had trouble growing indigo, but here in Michigan I can grow all the woad I want. Woad spreads so aggressively that some states have laws prohibiting it, check first.

Once you have grown woad and have leaves to harvest you can move onto the following process.


1. Cut woad plants, including leaves, stems and all above ground parts of the plants and chop into small parts. Do not finely shred or put the leaves through a food processor because it will be difficult to separate the vegetable matter from the dye later on.	2. Pack chopped leaves into a glass jar until full and carefully add boiling water to avoid breaking the jar. Put on lid, and let steep for 1 hour.	3. After an hour the water will have turned a dark red-brown. Pour the woad tea out though a colander with a linen cloth. Be careful to strain all herb matter out now while the dye is dissolved and the liquid is easy to separate.

Next, first make the solution alkaline by adding ammonia and then the liquid must be oxidized by beating air into it. Be sure to use non-sudsy, sparkling ammonia, as the regular sudsy type will produce large amounts of unwanted foam when air is worked into it. An eggbeater can be employed effectively, but an electric mixer is my choice. Put the woad liquid into a mixing bowl and add enough ammonia to give a pH reading of 9 or more on litmus paper. Most litmus paper will not read as high as that, but adding extra ammonia will not hurt. Turn on mixer to "whip" or medium to high speeds, making sure that the beaters are not completely immersed in the liquid: the goal is not to mix the solution, but to get air and oxygen into it. Keep working the solution for 10-15 minutes and watch as it darkens and some blue particles begin to appear on the top.
The now oxidized liquid has indigo-blue in it ready to settle out and purify. Put the liquid into tall, narrow jars and watch the darker indigo settle out over an hour or more. When there is obvious sediment on the bottom, carefully pour off the clearer solution while keeping the dark sediment intact. Add water to the sediment and let the indigo settle out again. Repeat these steps until you have a clear liquid with blue sediment on the bottom. You now have fairly pure indigo and water and are ready to evaporate the water off and powder up the indigo for storage. Pour off the water and pour the remaining water and indigo into a Silverstone or Teflon pan and let the water evaporate. When I tried other surfaces to dry out the indigo, the indigo stuck to it and had to be chipped off so I turned to more high-tech non-stick surfaces with great success. Indigo dried on Silverstone tends to peel up from the pan and can be easily removed, powdered and stored in a jar for further use.

The Woad Dye

Note- From this point on the dye will be referred to as indigotin since woad and indigo produce the same chemical just in different amounts, and indigo-based indigotin is virtually indistinguishable from the woad-based product. -R. The blue dye chemical indigotin, from indigo or woad, is the only natural "vat" dye in widespread use and though it is complicated to dye with, indigotin yields long-lasting and beautiful colors. Vat dyeing involves changing the normal indigotin, or indigo blue, which is not water soluble and will not bond to fibers, into another form called indigo white which will easily dye about anything. The indigo white is then returned to its blue form, and the now blue dye is locked into the fiber and is resistant to being washed out, which makes it a very powerful and long-lasting dye.
In practice, the fibers are dipped into a specially prepared dyebath of indigo white and when removed from the bath the dye reacts with the oxygen in the air and rapidly becomes indigo blue. The more often the fibers are dipped the deeper the blue color. Thus, the only truly complicated part of the process is preparing the dyebath.
To prepare the dyebath a "reduction" reaction to remove oxygen from the solution is required along with a change in the pH required to dissolve the dye. The reduction reaction was historically done by bacterial action in a vat of indigotin, aged urine, wheat bran and other additives that was a long and very strong smelling process. This was the traditional indigo vat or blue-pot. The fermented urine produced ammonia that shifted the pH level of the vat into the alkaline levels required for the effective use of the dye. More modern techniques involve chemicals such as sodium hydrosulfite or commercial preparations like Rit brand Color Remover and ammonia or some other alkaline agent.

Rowan's Simple Blue Pot

Warning: Indigotin dyeing will stain almost any surface from wood to Formica counter tops to stoves and refrigerators. If you cannot do this outside, cover all exposed surfaces and be very careful. To avoid staining hands, wear rubber gloves.

Materials Needed

8 oz. of white wool yarn
2 gallons water
1-2 Tablespoons powdered indigotin
Clear, non-sudsy ammonia
RIT Color Remover- 1 pkg.
Litmus Paper or other pH test system that can read 9 or higher

Directions

Heat water to a little more than lukewarm (100 degrees F. or so). The hotter the water, the more likely you are to damage the wool, so be careful.
Add ammonia by the Tablespoon until a pH reading of 9 appears. Do not make the dyebath too alkaline or damage to the wool fibers can result.
Sprinkle 1-2 Tablespoons powdered indigotin depending on how deep a blue you desire and stir thoroughly. From this point on all stirring of the dyebath should be done slowly and carefully to prevent extra oxygen from getting mixed into the solution.
Sprinkle in one teaspoon of RIT Color Remover and stir, wait five minutes and look for signs of a reduction reaction. These signs include a change in the color of the dyebath, especially a lightening in color, or the appearance of a coppery scum on the top of the bath. If this does not occur, repeat this step. 2 gallons of dyebath should not require more than one package of color remover.
Thoroughly wet the yarn in water before dipping. This presoaking will "open" the fibers of the yarn to more readily accept the dye, make for a more even color and keep small bubbles of air out of the dyebath. The water should be as close to the temperature of the dyebath as possible and try to support the yarn in several places so that the water weighted wool does not get stretched and loose its natural elasticity.
Carefully dip the yarn into the bath and slowly agitate, without making bubbles or stirring in air for about 30 seconds. Then gently lift the yarn from the bath, and let it air for five to ten minutes to re-oxidize and turn blue. This can happen very quickly and is fascinating to watch. Be careful where the yarn drips as drops of dyebath will leave a stain wherever they land. After ten minutes, successive quick dips can deepen the color, if desired.
When done, wash in a soap designed for hand-washable items and rinse yarn carefully and repeatedly until the rinse water runs clear and let dry.

Woad Paint

One reason many people are interested in woad is to make a paint to paint themselves in the fashion of the ancient Picts of British Isles as described by the Romans that were there. First- follow the directions for processing out the blue powder from the woad plants. If you are in the SCA, I have found people who sell chunks of the blue Scottish woad at the Pennsic War if you do not want to grow and process your own.

Second (and the part I have not played with a great deal)- mixing the blue powder into some kind of historical media that would work on skin. Egg whites whipped into a binder for tempera paint can work, but when it dries it does not stretch with the skin very well and can flake off. A fat-based media, probably something that is a solid at room temperature would work, but it will be greasy.

My personal guess at an ancient version would use lard and mix the blue powder into it. The blue will wash off of skin- it may take a bit of scrubbing, but blue woad will not dye the skin, only rest on it. However, the Modern Hengineering web site sets forth some interesting arguments and suspicions on woad's role in body paint and still provides a technique for using it as such. They also speculate on Woad and Modern Tribal Bodyart in Albion.

Suppliers

Woad Powder

BLEU DE LECTOURE in France. Fascinating site.
Woad, Inc. in England. Another great woad site.

Bibliography

Buchanan, Rita, A Weaver's Garden, 1987; Interweave Press, 306 North Washington Ave, Loveland, Colorado 80537. ISBN 0-934026-28-9. This is a wonderful book for the SCA dyer. There is lots of information about the cultivation and use of many ancient dyes, including woad, madder, and weld. Highly recommended.

Androsko, Rita, Natural Dyes And Home Dyeing, Dover Publications, ISBN 0-486-22688-3

Hurry, Jamieson B., The Woad Plant and it's Dye;1930 Reprinted by Augustus M. Kelly Publishers; Clifton, New Jersey 07012; ISBN 0-678-00779-9.

About this Page

Welcome to The Woad Page. I am a member of the SCA, or the Society For Creative Anachronism and that was where I first became interested in studying woad as a source of blue dye. This page is my effort to share what I have discovered over the years. -Rowan rowan@net-link.net