Patent ID: 6997962

Claim:
A method for dyeing a cellulosic material, wherein the method comprises: a) preparing a dyebath including particles of indigo pigment and a first additive causing the particles of indigo pigment to become electrically charged in a first polarity; b) preparing the cellulosic material for dyeing by applying a second additive to the cellulosic material to form a substrate on the cellulosic material having an ionic charge with a polarity opposite the first polarity; c) immersing the cellulosic material prepared in step b) in the dyebath prepared in step a) to cause the particles of indigo pigment to be ionically attracted to the substrate and retained thereon; d) chemically reducing the particles of indigo retained on the substrate to form a soluble leuco form entering the cellulosic material; and e) oxidizing the soluble leuco form to form indigo pigment within the cellulosic material.