Where is the Woad?

Where is the woad pigment in the plant? The pat answer I’ve heard is “in the leaves.” Not always, I just discovered. 

In one of the Michel Garcia DVD’s I bought, he makes prints from woad by simply mashing the leaves into cloth with a hammer. He then washed the cloth with a neutral dishwashing liquid (Dawn) and the non-permanent green washed out, leaving a print where the blue pigment was visible. I tried it, and realized the implications almost immediately. The pigment isn’t where I thought it was. I had been harvesting the huge outer leaves, with the idea to give the new leaves room to grow. While that pruning approach worked to make the plants grow like weeds, I had a hard time getting pigment. Here’s that first print.

You can see, that the blue is NOT in the big leaves or the stems-there are only the faintest traces of blue in the big leaves. In fact, another print made at the same time as this one, was left outside in the sun and rain. The green vanished completely, but the blue stayed. The blue-the desirable pigment we get from woad-is very stable over centuries, as the Unicorn Tapestries etc. clearly show. The other stuff in the woad “goes away” with the action of water and sun-and that is something I was able to put to good use, more on that later. The point is, the light green you see in the photo above is NOT the pigment, and will vanish. The blue is what I’m looking for. And I didn’t find it in the big leaves-it was far more concentrated in the small leaves!
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I want to do these woad leave prints on a regular basis to track where the pigment is-and when. On February 14 this year (2023) I made another print. I made the print in a slightly different way, so as not to use up so much of the bamboo rayon fabric; instead of folding the fabric in half and the leaves in the middle, I put paper on one side and fabric on the other. I also used a smoother surface underneath them, with the idea of not losing any of the print to the “valleys” of the concrete block I had used for the first print. The cloth side was blurry and harder to see than the paper side, so in the photo below you see the leaves arranged on top, and the print on the paper below. The print wasn’t as good overall as the one from summer, so maybe the rough concrete block was better?

Another surprise-the pigment had left the leaves, but was now in the stems! In summer, it was the opposite. Not only that, it was the larger leaves with the thicker stems that had the pigment, not the smaller leaves. So apparently in the colder weather, while the woad does not go brown and dormant or die like most plants here in Pennsylvania over the winter, the pigment in the plant moves around. So if I want to harvest pigment in winter, do what I mistakenly did in summer, and use the larger leaves! Interesting.

I had heard that once the plant looks purple, the pigment is destroyed. Yesterday I picked a selection that was purple in various places. Since I was at home and didn’t have a concrete block, I used one of the concrete steps to my house. The result was terrible, sorry, it makes the photo very hard to “read.” But if you look closely enough, there is no real blue, only purple and green, both of which are fugitive. Every source says the purple leaves are ruined for pigment production, and my own test confirms this.

My residency at the NCC East 40 began on June 1, so I didn’t get to plant the woad until a few days into June last year. This year I plan to sow in March as is considered optimum. Woad needs wet to germinate, and isn’t much bothered by cold. That’s next month! Now that I have the eco-print test (mashing the plant onto cloth and/or paper) I plan to do it both on the 2023 crop and the 2022 crop, to see how much pigment is where when! This will give me much more specific information than I have been able to find in any source. 

Finally, there was another huge “Aha!” moment that I had inspired from the eco-print process; I can use sunlight as well as water to help get rid of the impurities. Last summer I was processing a large batch of woad leaves that I later learned low pigment content from doing that first eco print. I could tell there was pigment, but there was also a lot of the fugitive yellow that I needed to get out. I did what Garcia showed in his DVD, which is to wash the pigment. You use a fine mesh cloth to catch the pigment, but the fugitive yellow is soluble in water and gets washed through. Every time I rinsed, the pigment got less green looking (from the fugitive yellow) and more blue. But after a half-dozen washings, and all that waiting for the liquid to go through the cloth to the bucket below, I got frankly tired of my kitchen being a mass of buckets and strainers. I dried out the pigment, put it in glass, and put it in the window that gets the most sun. I shake up the little jar periodically, and it continues to improve, at this point I’ve actually used a little in in some paintings. Now that the eco prints are helping me to understand what to harvest when, I won’t have to deal with such an annoying batch again!