Woad Dye Bath Alchemy – 1st Session
Woad leaves are cut up and soaked before boiling and simmering for an hour. Remove leaves, then dye bath needs soda crystals, before whisking for 10 mins until froth forms. Woad dye bath is ready when there is a pale blue or (in this case) pale green froth. Reheat dye bath to 50 deg. then add spoon of sodium dithionite to remove oxygen. The water goes limey green. Submerge silk. Lift after a while to see strength of blue (which shows in oxygen).
- Boil woad leaves – until liquid is sherry coloured: it changes quickly, but simmer for an hour.
- Add soda crystals – until alkalinity reaches 9-10. Use litmus papers from plant dye suppliers.
- Whisk liquid – until froth forms. A tiring 10-15 mins but liquid can also be poured from height from one pan to another making bubbles. (for a whisk break)
- Heat dye bath – to 50 deg again. Set aside 20 mins. (use cooking thermometer)
- Add desert spoon sodium dithionite – to remove oxygen. Add enough until dye bath turns limey green.
- Place silk in liquid – carefully without creating air bubbles. Submerge. Leave for 20 mins. Woad colouring occurs quickly after exposure to air, because the dye bath had the oxygen removed by sodium dithionite; re-exposure to oxygen turns it blue.
- Remove fabric – and rest. Watch it turn blue in air. (mine went turquoise on ahimsa cream silk using pond water)
- Rinse out – when colour as dark as will go, hang out to dry.
First Woad Result
Careful – woad dye is fugitive!
The dye on the silk was uneven (see photo); so I re-heated the dye bath again, added the same chemical again, and replaced the fabric, but the magic had gone, the deep turquoise blue disappeared! The result was a pale grey blue, which looked dark in the rinse sink, but dried quite pale. Still nice and evenly dyed, and highly usable. Good to have the photograph of the original dye result before I annulled it!
With any of the plant dyes, its good to keep the dye bath liquid, and see what colours can be made from the mixture, after the first dye has been successful. In the case of woad a lighter grey blue was achieved. By addition of iron liquid colours go more sombre, grey-brown; but other colours could be added. A small amount of madder might have turned the second dye bath lilac.
See many dye procedures on my Natural Plant Dye Pinterest Board.