The history of Woad is nearly as interesting and varied as the history of the color red. Blue is, to the full, as rare a color as red in the annals of natural dye use. In history, there are only four sources for a permanent natural blue dye, and there is only one molecule that gives that color. Indigo is the molecule, and it is sourced from the Indigoferas species, Chinese Knotweed, Woad, and ironically enough, the mollusc that was once used to give shellfish (Tyrian) purple.
Woad, Indigo, and mollusc indigo were known by the Ancient Egyptians. Linen fabric has been found in tombs in Egypt, with all colors faded, except the blue. While molecular science can tell that some of the blue is undoubtedly an indigo molecule, whether that molecule was sourced from indigo genus, woad genus, or shellfish remains unknown. All indigo is molecularly identical, no matter its source.
Shellfish purple differs from Indigo by a single bromine molecule. Thus, when the purple was dyed, depending on the weather conditions, the purple could turn to an indigo blue. The colours, including the indigo blue, used in creating the “Tabernacle” in the Old Testament, were all sourced through death. Reds were gotten from the death of insects, purple through the death of shellfish, and the blue was primarily sourced from shellfish purple. In the OT, the words used to describe the colours actually describe the mollusc, and insects from which the colors are sourced rather than the color itself. 
If you are wondering about that, a quick look up of Exodus 25:4, in a version with the Strongs word connections, will show what the words translated as “blue, purple, and scarlet” actually are and mean in Hebrew.
The deep history of woad is a rather interesting one. It was known in Egypt, Italy, and Israel quite early. One evidence of this is that the woad plant bears the name of “Isatis” in all three languages, a highly unusual situation. Woad originally flourished in Egypt, Turkey, and the warm climate of the Mediterranean. Somehow, however, it spread along the routes of human migration and steadily penetrated further north, as well as further East. Finally, woad lost much of its Mediterranean association and became associated with primarily northern tribal groups, the Picts, Scots, and Celts of Old Britain being primary examples. Though woad has also found a strong place in Chinese medicine, though not so much their dye traditions as they also had access to other indigo sources.
Woad and the Picts
Whenever I begin talking about woad, the first question I get is “what?” Even among natural dyers, woad is a relatively unknown plant. Among normal people, even writers, in today’s culture no one really knows what dye plants are and if you mention a more obscure one, well the “what” usually shows up fairly quick. After trying to describe it as a plant a few times, I finally gave up and will say, “woad, you know the plant that the Picts were said to have painted themselves with?” Sometimes that answer works, and sometimes it does not, and sometimes it sparks an argument over whether the Picts actually did paint themselves as their name implies.
The term “Picti” (or “Picts”) was a Roman term that basically meant “painted ones” referring to that people’s habit of painting themselves before battle. Some claim that the paint they used was woad while others say it was not. It the paint was made from woad, it was likely the foam off the top of a woad indigo fermentation vat that was the color source, not the dye liquor itself.
Of course whether or not the Picts actually used woad for their war paint is open to question. However, my bigger question is how woad got from the Mediterranean to Britain in the first place. The only answer that makes sense is that, as humans migrated north into the forest of Europe, they also carried the seeds for their dye plants. While originally a warm climate and Mediterranean plant, woad ended up being adaptable enough to thrive away from the warmth of the sea and clear up into Iceland, Norway, and Denmark.
Woad and the Celts
A similar situation to the Picts, the Celts were more in Ireland and Wales than in Scotland and Britain. It is believed that they also painted, or tattooed, themselves with woad in some way. Certainly woad was known to the Celts, and was used on their clothing and fabrics, and possibly in their religious ceremonies as well.
There are legends of certain happenings around the woad vat, with the Celts. Including those of someone speaking a “joking” command to the vat, and the vat doing what they said. This included turning the fabric grey, or purple instead of blue, or having a strange line in the fabric due to the dye laydown.
These legends are fascinating for me, as a natural dyer, since I wonder whether it was a mistake in the vat that could have been easily corrected, or if it was something completely off the wall. While the woad vat is complicated, once you understand some of the chemistry behind it, it can be quite interesting to see what happens when you change a few minor variables. Thanks, in part, to experimenting I am fairly sure that you can get more than blue from the woad vat, and that without over-dyeing or mordant related color changes.
Woad And The Scots
Anyone who has watched Brave-Heart as seen the blue war paint that Wallace supposedly wore, that was supposed to be sourced from Woad. While that may be true, it is more likely that they were not using those scare tactics any longer, though Woad itself was well known throughout the highlands and nearly every family would have had their own woad-vat going. Blue, particularly light blue, was a color associated with peasantry and commoners, while the brighter and more expensive colors were associated with the upper class. It was only a few hundred years after Wallace that the insurgence of Indigo from India and other locations began to gain strength, and it did not take woad long to fall out of favour as a much lighter color than Indian indigo.
In England and France, before Indian Indigo gained ascendency, the woad farmers and traders were often among the richest in the district. Toulouse France actually gained its wealth thanks to woad, and many of the schools and universities in the area were initially founded by those who profited from Woad, usually as traders. Of course, the advance of Indian Indigo and its ease of use eventually brought the downfall of woad, and except as a fermenting and color fixative adjunct to the Indian Indigo fermentation vat, woad was no longer interesting to the dyers of the time.
At least, woad was not interesting until Napoleon was blockaded during The French Revolution.
Woad in the French Revolution
After Napoleons rise during the French Revolution, Britain and the other European monarchies instituted a naval blockade of the French coast. This effectually put a stop to all Indian merchantmen sailing to France, and cut off the entire supply of Indian Indigo from French shores. However, the French army wore blue, but how can you dye blue without Indigo?
Re-enter the Woad plant.
While it was known that, once upon a time, woad was a reliable source of blue, the years of Indian Indigo’s ascendency had caused all knowledge of how to create or dye from traditional Woad balls to be lost. Unless something changed in the dye fields, and that quickly, the army would end up lacking uniforms of the correct color. And so instead of changing his uniforms, Napoleon instituted a contest to see if they could get a similar indigo product from Woad as they had been shipping in from India, and that the dyers were accustomed to using.
The winner of the contest managed to create a simple extraction method for woad that, with proper work, resulted in a powdered indigo dye product. Napoleon’s army was saved, and marched forth to battle with indigo uniforms dyed with woad. Now, we have to thank Napoleon’s stubbornness and determination to continue in blue uniforms, as if he had not been stubborn we would never have had any idea that there was a non-woad-ball method to extract indigo from the woad plant. And, instead of having picturesque uniforms, the French army would probably have been the first army to institute brown uniforms (and we would have ended up with camouflage much sooner).
Woad in Modern History:
It is this method, developed due to a naval blockade during the French Revolution, which is now the modern method for extracting indigo from woad. I first encountered a recitation of this method from a very useful book. Jamison B. Hurry’s The Woad Plant and Its Dye, now unfortunately out of print. The method undergoes slight adjustment depending on who you talk to, though its basic premise always remains the same.
After the French Revolution, the biggest challenge to woad indigo was that it has a much lower yield per kg of leaves than Indian Indigo. The average for Woad yields appears to be in the range of 2-6 grams of indigo per kg of leaves, while Indian indigo sits in the 12-16 grams per kg of leaves range. However, I firmly believe that with proper experimenting and procedural techniques, woad could become the equal of Indian indigo in yield. In the next part, I will discuss some of the reasons I believe Woad Indigo could rival Indian Indigo in yield and color, and my own experiments that ended up forming and supporting this belief.
Back To You:
What other history of Woad are you aware of? Is there something that you have heard that you would like to add, or challenge?
Leave a comment! I love hearing from you.