Woad (Isatis tinctoria) is a type of Indigo dye produced from the leaves of the plant and is common in Europe and Egypt. Dyeing with woad goes back in time quite a ways - from my own research, I know civilizations were dyeing with woad back in Halstatt times, circa 800 BCE, and likely quite a bit longer in locations such as Egypt. Per J.N. Lile's The Art and Craft of Natural Dyeing, woad dye is derived from glucoside indican, which is a colorless substance present in the indigo plant. Indigo blue (the oxidized form) is insoluble in water, and will not dye material permanently - the compound must first be reduced chemically to "indigo white" or "leucoindigo" in which form it is soluble in an alkaline solution. Dissolving woad in an alkaline solution yields a yellow/greenish colored bath that turns blue when oxidized - dipping material into the bath comes out yellow/green and then will change to blue as the chemical is exposed to air (oxygen). This yields a dye that chemically binds to the cloth vs. a film that sits on the surfaces and would rinse clean with water. Lile suggests that old urine, lime water, potassium carbonates and/or wood ash all likely would have been possibilities for alkaline solutions for historical dyeing.
We used soda ash and a chemical called sodium dithionite to achieve our alkaline solution. I read about 10 different recipes and ended up deciding to do a test vat first to try out Claire's suggested recipe (which was, from my memory, 1:1:1, so 10 g woad, 10 g soda ash and 10 g sodium dithionite) - that may or may not have been correct, but that was what I wrote down in my notes! I had some measuring tools, but no scale, pH paper or thermometer (so I felt I was doing in fairly imprecise, but - with the exception of the scales, I think it would have been much like this anyway). I mixed the soda ash with roughly 200 ml of warm water and separately created a paste with the 10 g of woad (with 30 ml roughly of water) - we then combined them in a soda ash solution and allowed 30 minutes to pass. We then added that solution to a vat of 2.5ish liters of warm water and sprinkled 10 g of sodium dithionite onto the surface. Note: fiber was soaked overnight to remove oxygen from the fibers and we heated river water in an iron kettle, so there are a number of uncontrollable factors we were likely dealing with related to the composition of the water and adding iron into the mix. I also used plastic tubs because they were more affordable than copper cauldrons.
Materials:
Before pictures of linen and wool for dye experiments (linen is the same color as in the cap picture and the wool is a dress I cut out):
First vat attempt:
I knew something didn't look quite right because we should have seen a coppery sheen on the top of the vat and the vat itself should have appeared more yellowish green. Directions I had printed off from the site I ordered the dyeing materials from (http://www.woad.org.uk/) said to try adding more sodium dithionite. I did that, which made the color more yellow, but didn't include the coppery sheen I was looking for. I decided to go for it, since it was just a small test. Here's some video/photos from the result:
Vat after adding more sodium dithionite:
Here goes nothing:
Dyeing Video:
I decided to do a second dip (which was suggested) to see what happened:
The woad took very slowly (as you can see from the videos) - this may be because the pH wasn't quite right.
First Day Results (I did a piece of linen fabric and bleached linen thread) - both are still wet in the photos:
I was pretty thrilled to have dyed my materials a different color (even though it took more than 10 minutes) and it gave me confidence going into day two!
For my second day of dyeing, I decided to stick with the formula that worked the day before... I just made a lot more of it! I used 100 g of soda ash, 100 g of woad, and 200 g of sodium dithionite (rough numbers here, I didn't have precise measuring tools, but knew how much I started with the day before). I dissolved the soda ash in 3 liters of warm water and the woad into 300 ml of warm water to make paste. I then mixed the two together and waited for roughly 30 minutes - after that, I submerged the solution into roughly 35 liters of warm water, added the 200 g of sodium dithionite to the surface, and kept it close to the fire to stay warm (that was a lot of river water to heat!!). That solution rested for an hour.
This time, we got the coppery sheen on top of the vat, but the dye vat was much darker than the day before. I didn't have more materials to play with, so we decided to just go for it as it was! I dyed my cut out wool dress, some extra material, and redipped my dyed linen from the day before. Reginleif dyed a beautiful piece of diamond twill linen!
Woad/soda ash solution (yes, I used a stick to stir):
Dye vat with coppery sheen and warming by the fire:
Wool dye video (much faster this time around, so maybe the pH was closer to what it was supposed to be):
Dyeing results (1st dip):
Dyeing results (2nd dip):
We rinsed our work in the river - the water's current helped take the excess dye out of the fabric:
Final Result (Wool - see starting cream color at the beginning of post):
Final Result (Linen - see starting natural color at the beginning of post):
Final Result (Wool):
Final Result (Reginleif's Linen):
I'm very pleased with the results of this experiment - the blue is a lovely color and I look forward to sewing my dress and head covering!
