OKANAGAN ART WORKS
The dyeing process is a straight forward step-by-step process. The leaves are harvested by cutting off all the leaves from a plant, leaving the young centre leaves intact. The plant will grow new leaves from the crown and may be harvested again in 4 to 6 weeks.
43
Add soda ash to raise vat pH to 10. Oxidize vat. There will be a colour change in the foam at the top of the vat. It will begin as yellow and then change to green and then to blue.
In the south east Okanagan climate woad leaves can be harvested 2 or 3 times in a growing season. July, August and September are ideal. The most indigo is obtained in the first harvest, with subsequent harvests producing less pigment. The leaves need to be washed and then boiled in a pot of water with vinegar added to it to reduce the pH level. Boil the leaves for 1 minute and immediately plunge the pot into cold water to reduce extraction vat temperature as quickly as possible to room temperature. The leaves should remain in the extraction vat for 20 minutes. Remove the leaves from the extraction vat and squeeze out excess moisture before setting aside. These leaves may be used for a boiling water dye bath and will give varying shades of pink and beige, depending on the genetics of the plant.
Continue oxidizing till the foam changes from blue, back to green and then to yellow again. Allow indigo that is suspended in the vat to precipitate out -- 4 to 8 hours -- up to 72 hours. Filter or decant liquid. I use a turkey baster to remove the top liquid, without disturbing the indigo sediment. Indigo will be visible as a blue sludge in the bottom of the vat. Allow solution to dry or use immediately to dye in a reduction vat.