Indigo or also perhaps existing sulphur dye is present as a ring dye around the warp yarn. The dye is applied to the yarn in several layers; the outer layers are often not perfectly fixed and often come off in the first treatment baths, which can lead to backstaining during the treatment steps.

Dark denims bring an extremely high load of indigo pigments into the first treatment baths. In the desizing and stonewash processes, disperse agent systems support the removal of surplus indigos and reduce renewed build-up.

It is also possible to block the fibres to a large extent against contamination from the removed indigo.

Both systems in combination represent the current state of technology regarding anti-backstaining.

CHT worldwide