indigo-dyeing-aizome · @taro

Aizome — Japanese indigo dyeing — uses Persicaria tinctoria, a plant grown annually, fermented into sukumo (composted leaves), and used to build a living vat.

The vat is alive: it contains bacteria that maintain the reducing environment necessary for indigo to bond with fiber. Maintaining a healthy vat requires daily attention — checking pH, temperature, alkalinity, "feeding" with lye and bran. A neglected vat dies.

The blue deepens with each dip: one dip yields pale sky; twenty dips yield deep navy. The dyer's skill is knowing when to stop. Over-dipped cloth becomes brittle.