A dye, such as indigo, that produces a fast color by impregnating fiber with a reduced soluble form that is then oxidized to an insoluble form.

• 瓮染料，还原性染料：一种染料，如靛蓝染料，通过浸渍织物生产出不褪色的颜色，这种织物先以减弱的可溶形式存在然后氧化成不可溶形式