Madder, indigo and abrash

Before synthetic dyes reached Persian weaving in the later nineteenth century, every colour on the loom began as something that grew. The dyer, rangraz in Persian, worked with a short list of sources and a long list of techniques: how long to soak, how many times to dip, which mineral salt to use as a mordant so that the colour would bite into the wool and stay.

Red came from madder, the root of Rubia tinctorum, called runas in Persian. With alum and repeated dipping it gives everything from brick to rose to a deep aubergine. Blue came from indigo, nil, fermented in a vat; the wool comes out of the vat green and turns blue in the air, darkening with each immersion. Yellows came from weld, from larkspur (isparak), and from pomegranate rind, which is rich in tannin. Walnut husks gave browns. Green was usually made twice over: indigo first, then a yellow bath on top, so that on an old rug a green can fade unevenly towards blue.

Browns and blacks were often fixed with iron, and iron slowly eats wool. On many old rugs the dark outlines have worn lower than the colours around them, so the pattern stands in faint relief, as if engraved.

Abrash

Look along the field of a village or nomadic rug and you may see a band where the red turns slightly browner, or the blue lifts towards slate, running straight across the rug from side to side. This is abrash, the rug trade’s word for these shifts. Wool was dyed in small batches, and no two batches matched exactly; when a weaver came to the end of one skein, she tied on the next and carried on. Commercial workshops worked to avoid it. In a village rug it is often the loveliest thing in the field.