How Jeans Got Their Fade
- Indigo by Jenny Balfour-Paul
British Museum, 264 pp, £19.99, October 2000, ISBN 0 7141 2550 4
- Mauve: How One Man Invented a Colour that Changed the World by Simon Garfield
Faber, 222 pp, £9.99, September 2000, ISBN 0 571 20197 0
Human beings have an insatiable appetite for colour, but the everyday gaudiness of our world is modern. We can dress as showily as birds (including crows – 70 to 90 per cent of clothes are dyed black) because we have found ways to stain pale yarns in strong colours. During the last 150 years the whole spectrum has come to be cheaply available, as it has become possible to synthesise dyes which previously had to be extracted from plants and animals.
Dyes are tricky. Unlike paint – pigment carried in suspension in a medium which sticks it to a surface – dyes must adhere to the substrate molecule by molecule. Some do it directly; other dye/fabric combinations need an intermediary – a mordant – in which to dissolve the dye to make it bite. Consider what used to have to be done in order to dye with indigo (the process has certain things in common with brewing). Leaves from one of the plant species which contain indican, the precursor of the dye, are steeped in a vat. Lime (or urine, or wood ash water – something to keep the contents alkaline) is added. Fermentation turns indican into indoxyl. Cloth can be dyed directly in the fermentation vat, in which case the indoxyl is oxidised to become indigo when the steeped cloth is exposed to the air, and the liquid which looks greenish yellow in the vat turns blue.
If the dye is to be stored, however, it must be processed further. The fermented liquid is run into another vat and aerated by stirring. Before machinery took over, large-scale indigo producers had slaves or coerced labourers march up and down in the tank of caustic, evil smelling oxidising indigo. It was a horrid job. At the right moment (knowing when required skill) stirring was stopped and the indigo which had been precipitated was harvested as a paste from the bottom of the vat. This, dried and prepared as balls or cakes, was the exportable product.
To use it, the dyer ground up the ball of dye and dissolved it in a vat of alkali. This reduced the indigo to leuco-indigo. The solution did its magic as before. The cloth when taken from the vat of greenish dye turned blue on exposure to the air.
In Indigo, Jenny Balfour-Paul glosses these processes scientifically. The first surprise is that indigo, the dye of dyes, is in some ways more like a pigment. It needs no mordant, even on non-absorbent fabrics like cotton. Tiny particles, not individual molecules, adhere to the fibres, which is why it rubs, giving stonewashed jeans their pale, worn look. In some parts of the Arab world, rub-off onto the skin is thought to be good for the complexion.
Balfour-Paul has grown indigo and sought out dyers in Europe, Africa and Asia. Her pictures show the materials, from live plants to vats and balls of dried indigo, and the processes of dipping, decorating (often by tie-dyeing, keeping parts of the fabric undyed with resists or knots) and glazing with mallets and rollers. She shows how the indigo spectrum runs from pale blue to near-black (although it is really broader than that – an Indian dye book describes colours from ‘regal purple’ to ‘light canary’, all made in Gujarat from indigo combinations).
The full text of this book review is only available to subscribers of the London Review of Books.