I planted alkanet in the dye garden this year in hopes of purple dye (oh, how I wanted that purple dye) but from all that I'd sown only one alkanet plant grew. Just one. Well, that's not enough roots to dye anything! Sigh. I guess there's always next year.
But what did grow (and very nicely I might add) was the woad! Just five plants gave me 350g of leaves.
I put them in a large glass jar and covered them with hot water, letting them steep for about 45 minutes.
Then I strained the leaves out, reserving the brownish-red liquid and added just a bit of washing soda to make the dye more alkaline. This turned it a dark green colour. In order to introduce oxygen I poured the liquid from one jar to the next several times over (what I was looking for was the foam on the top of the jar to turn blueish in colour).
A bit of sodium hydrosulfite (perhaps next year I'll be brave enough to try the old-time recipe using "mature", in other words it's sat around for a few weeks, urine) was added to remove the oxygen from the dye vat and the wool was carefully (so as not to introduce air bubbles) placed under the surface of the liquid. And there it sat in it's oxyen-free environment for twenty minutes, at which time I could tell that it was a nice bright yellow colour.
And now for the magic...
As the wool is re-exposed to oxygen it turns blue! I've read about the process (about a hundred times) but it was still so exciting to see! So exciting, in fact, that I took a video:
I did successive batches of wool (eight in total) in the same vat and each time I got a slightly lighter shade of blue. The roving on the left of this picture (the pink one) was dyed in a bath of woad leaves that were boiled and dyed in the usual method (not a dye vat as I described above).
Most definitely ordering more of this for the dye garden next year. I see a blue sweater in my future!