DYEING WITH INDIGO AND FRESH WOAD

For my first short holiday this year I chose to join a 3-day workshop in the middle of nowhere (Harz, Germany, to be exact) to learn about making indigo vats and working with fresh woad. I experimented with simple 1-2-3 vats (organic vats) before, following the recipes of Michael Garcia. Some of them worked and some didn't. I couldn't figure out my mistakes so I decided to join Karin Tegeler this summer and ask her all my most burning questions.

 
What you need

For those who never heard about dyeing with indigo, let me tell you a few words about what are vats. The process of dyeing with woad is similar to dyeing with the indigo plant. The pigment contained in the leaves is not soluble in water, so to be dissolved, it must undergo a chemical change - reduction. First removed from the dye pot, it combines with oxygen in the air and reverts to the insoluble blue. This oxygen-free dye bath is called a vat. There are many recipes for making a vat (I read 19 only this weekend) but we tried out just the most common ones.

We started the course with making a basic, non eco-friendly vat, using synthetic indigo, ammonia and hydrosulfide.  Pigment extracted from the true indigo plant is never fully clear and always holds small residues of other pigments that the plant was containing. In the nature, plants never have only one pigment in them but a mix of many, which manifests itself in the final results. Buying the pigments obtained from plants you can never be entirely sure how much actual pigment is in there. Therefore, for our first vat we used a clear pigment made in a laboratory, following the chemical structure of indigotin.  The results pulled from this vat were very clear, pure navy blue.

They all looked too artificial for my taste, but if that's the color you like, pure synthetic indigo should be your choice. We also made an organic vat, using the same pigment, but with lime instead of ammonia and fructose instead of hydrosulfide. This vat needs much longer to reduce. Instead of one hour (ammonia and hydrosulfide), we waited two full days before we could use it. The results were very similar, though, and it's a recipe friendly for the environment and not toxic to people.
You can find many recipes for organic vats if you search for 1-2-3 vats online. When I first started experimenting with indigo and woad, I followed Maiwa resources and I can only recommend them. You can make indigo organic vats using other ingredients instead of fructose too - henna, madder, dates, ripe fruit, but also iron.  Making the latter, remember that high concentrations of iron can damage protein fibres.

Left, from the top:

• silk, synthetic indigo, hydrosulfide and ammonia vat

• cotton, synthetic indigo, fructose vat

• silk, fresh woad leaves

Right from the top (all wool):

• synthetic indigo, hydrosulfide and ammonia vat

• synthetic indigo, fructose vat

• synthetic indigo, hydrosulfide and ammonia vat, late dip

• fresh woad fructose vat

• fresh woad hydrosulfite and ammonia vat

• fresh woad fructose vat (left) and hydrosulfite and ammonia vat (right)

Later that weekend we attempted making the same vats using fresh woad leaves instead of synthetic indigo powder. Woad, unlike true indigo, doesn't contain indigotin but another substance - isatin, that develops into indigotin when exposed to the oxygen. After cooking freshly cut leaves for just a few minutes and then aerating the isatin, we proceeded just like with the indigo pigment. For a 20l vat we used around 20 plants worth of woad (it shrinks when cooked, so just enough to fill the pot). After cooking and straining the brown liquid, we cooled it down and exposed to the oxygen by pouring it between two buckets. When the dye cooled down to just under 60C, we proceeded with the same vat recipes we used when working with indigo.

These results were much different to the synthetic color. To me, they look more alive and natural, and even though they are less shiny and more greyish, I enjoy their subtle tones. You can see that the ammonia and hydrosulfide vat produced a slightly darker tone, but the organic fructose vat worked almost as well, without hurting the environment along the way.

On the last day of the course we were offered to take some of the home-grown woad leaves home and I happily accepted the offer. I've read about The Dogwood Dyer's experiments with fresh indigo leaves and I was curious if I could replicate her beautiful results using woad. On the same night I arrived home, I put a decent amount of fresh leaves into the blender, poured very cold water over them and shredded. I strained the leaves immediately and got a yellow-green liquid. I placed wool and silk fibres in it and waited for about 5 minutes. When I took them out, they were juicy green but after 2h of drying outside they turned nice pale blue (wool) and mermaid turquoise (silk). Many more fibres landed in the dye bath that night, producing some paler blues and sweet greens, until the liquid turned very dark and refused to color any more fabric. Now I will have to test them for light fastness but I'm already very excited about growing more woad next year.

Top left: fresh woad leaves

Left, from the top:

• wool, 2nd dip

• wool, 1st dip

• wool, 3rd dip

Right, from the top:

• cotton, 2nd dip

• silk, 1st dip

• silk, 3rd dip