At last I've harvested and processed the woad that's been maturing over the summer.
To the left is the original colour of the raw silk I've cut out into a rather stylie top. In the middle - the same cloth after 8 successive dippings in the woad bath - for 15 minutes a time and then the aeration for a further 15 minutes after each dipping. The silk hanks have been in and out for 10 dips and are a deeper shade.
Isatis tinctoria - woad in flower
silk out of the dye bath after 3 dippings
Here's how it all happened......
once upon a time I met an old gent at the Craft Out West fair and had an indepth discussion with him about ecodye colours, and co-mordanting with the pots only ( no added chemicals. )
The 84 year old told me he couldn't find decent cloth anywhere to tailor himself a pair of trousers - from his own wool and spun and dyed by Himself - and he would have to resort to building his own loom.....and then he sent me the MOST wonderful package of fresh living viable madder roots wrapped in damp spaghnum moss and two little containers of his own weld and woad seed.
So, this weekend when my partner and I spent 5 solid hours processing 6lb or 2.7 kg of fresh woad leaves picked from the garden into a range of blue hues - depending on the fabric or fibre.
After extensive research, we decided to go with the method described by Sarah Dalziel http://www.fiberarts.ca/woad%20extraction.html
We found this the easiest and most comprehensible. We still needed specialist equipment - we borrowed a laser thermometer and a commerical pH meter from a friend. We used white vinegar to reduce the pH to 3 at the beginning of the process and soda ash (sodium carbonate) to increase it to 10 before oxidising.
We used a heavy duty drill with a beater attached to oxidise the dyebath. It foamed up quite a bit but it was easy to see the colour changes during the process. At the end when we expected the froth to go back to yellow, we had to scoop slightly below the top froth ( which was a gorgeous blue) to see the yellow tinge.
aerated woad dye turning BLUE
We would also have a couple of bags of crushed ice available next time to get the dyepot cooled faster. Cold water in the bath with a couple of random slicker pads was not that efficient.
It would be a great deal easier and quicker to bring the dyepot back to boiling after adding each few handfuls of ripped leaves if we used gas. The ring on the stove is too slow, especially when your stainless dyepot has a wobbly bottom and heats irregularly. AND - we'd pick a day when the inside temperature was NOT 28 degrees and upwards.....maybe an early morning would have been more efficient.
But I think the results are well worth the effort and I can't wait for next season. Fortunately I now know I can make successive monthly pickings of the woad leaves.