Dyeing with Woad

Woad is a herb that looks like a cross between spinach and sugar beet and undergoes a process to produce the blue pigment. In some areas of the world it is regarded as a noxious weed because of infestation. 'Indigotin" is the blue precursor found in the woad plant (Isatis Tinctoria) and has the same make-up as that found in true indigo (Indigofera Tinctoria). The colour is generally referred to as 'indigo' regardless of its source. Varying shades, from the palest sky blue to rich, dark cobalt, can be achieved in the dyeing process. A pretty pink can also be extracted from the woad leaves when all the blue has been removed.

A highly interesting chapter about dyeing with woad is given in Jill Goodwin's book "A Dyer's Manual", and Jenny Dean's book "Wild Colour" clearly illustrates the various colours available from the leaves and seeds. For more information about these books, please see our Additional Resources page.

Woad has its own alchemy in the dyeing process and it is fascinating to see. Indigo only permanently fixes to fibres when it is in a reduced state known as indigo white. The item for dyeing is immersed in the mixture and, when lifted out, it turns from yellow to green and, finally, to blue when it oxidises in the air!

The benefit of growing woad again as a colouring material is to offer an alternative to the harmful chemicals used in synthetic indigo dyeing whilst using a sustainable resource. Synthetic indigo is made industrially from three toxic chemicals: aniline, formaldehyde and hydrogen cyanide, which are derived mainly from non-renewable resources. These are reacted together to form an intermediate, phenylglycine, from which synthetic indigo is made.

However, the indigo we produce is extracted from the woad plant and no industrial processing is used in its manufacture. The Soil Association, in the context of their Organic Textiles Committee recommendations, has approved the chemicals used. There are no environmentally unfriendly waste products involved in producing natural indigo from woad.