Black walnut extract is obtained from the bark of the tree and also from the green husks of the fruit. Domonique Cardon has called walnuts “great living laboratories of dye production.” Walnut is a substantive dye and can be used without a mordant. It can be used alone or to give extra depth in combination with other dyes. Historically it has been used with madder (both rubia cordifolia and rubia tinctoria). Walnut responds well to overdyeing with iron producing rich grey/browns. Dye at 30-50% WOF.