The Japanese indigo stalks that haven’t been cut are covered with beautiful pink and white flowers. I’m hoping they’ll set seed for next year but it’s hard to say as my garden is bordered on the south by the forest and only the tips of the plants get several hours of sun on sunny days (and we have lots of rainy and overcast ones these days!)
The first dyeing I did used the thiourea dioxide/Spectralite method as outlined in Rebecca Burgess's book ‘Harvesting Color’. I decided to try the vinegar method. Different recipes list different proportions of ingredients and most use 25% or 10% acetic acid/white vinegar. I just have 5% white vinegar and the approximate recipe I used was:
200 gm leaves
100 gm fibre (though I was able to add more)
3 litres water
90 ml 5% white vinegar (30 ml/litre water)
I soaked my fibre overnight and the next morning picked stalks of the indigo and removed and weighed the leaves.
I cut the leaves into small pieces, put them in a pail and covered them with the water into which I’d mixed the vinegar.
I used a handheld blender to chop the leaves. After several minutes the water became bright green and I strained it through a strainer which I’d lined with a piece of silk chiffon. (I wanted to keep any pulp out of the dye bath and later put the silk into the dye bath to dye it). I covered the same leaves with water that had been mixed with 30 ml 5% acetic acid/litre water and blended once again. This was strained into the dye bath as before and the leaves squeezed out through the strainer. I put the leaves on the compost pile but I’ve read that they can be used to dye a pinky-beige. The liquid in the dye bath was a beautiful bright green.
I then added the fibre to the dye bath. I dyed a couple of rovings first to get the strongest colour. After soaking for an hour I removed them, being careful not to add any oxygen to the bath with dripping, added the rest of the fibre and left it to soak for an hour. As there was still some colour left in the bath I later added more fibre.
Taking the fibre out of the dye bath is magical! It turns from green to turquoise blue as you watch. This vinegar method produces a different colour than the thiourea method which gives blues similar to those given by the Indian indigo vat. Living as we do by the ocean, my fellow dyers and I call this lovely colour seafoam blue.
I have an Indian indigo vat which I plan to keep for cellulose fibres which dye very well in it but not so well with the Japanese indigo. However, I prefer the Japanese indigo for dyeing rovings as it’s gentler.