简介:Indigo is a so-called vat dye, which means that it needs to be reduced to its water soluble leuco-form before dying. The reduced form is absorbed into the fibres, and when oxidized back to its blue form it stays within t简介:Indigo is a so-called vat dye, which means that it needs to be reduced to its water soluble leuco-form before dying. The reduced form is absorbed into the fibres, and when oxidized back to its blue form it stays within the fibre. Earlier the reduction and dyeing was done with fermentation. Nowadays, the most of the reduction has been done chemically by sodium dithionite.详细>