| Woad harvest starts in August. On a commercial scale, one acre of land produces about 10 tonnes of leaves twice a year. One tonne of leaves produces 2 lb of woad powder. Three kilos of leaves from my allotment, which is the most I can process at one time, produce just 8 g of powder! To extract the pigment I pick and tear the leaves, steep them for 40 minutes into hot water. Then I add soda ash and whisk the liquid for 10 minutes. |
| | The woad pigment is insoluble in water. It is necessary to remove the oxygen from the water to create the soluble woad. This is done either by fermentation with urine or bacteria, or by using a chemical like colour run remover. Wet fabric is dipped in the woad vat and removed after a while. The fabric is yellow when exposed to the air, and it slowly turns blue. In the past dyers who worked with woad had blue nails; I make sure I use rubber gloves. |
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