GB/T 2402-2012 "Cationic Dyes—Determination of Staining to Other Various Fabrics in Dyeing Acrylic Fibers" specifies the method for determining the degree of staining of cationic dyes on other fabrics during the dyeing of acrylic fibers. The principle involves dyeing acrylic fabric together with a standard multifiber adjacent fabric in the same bath, and assessing the staining according to relevant standards. The test requires standard dyeing equipment, qualified multifiber adjacent fabric, and a grey scale for assessing staining, supporting both instrumental and visual rating methods. It provides a quality assessment basis for the application compatibility and dyeing safety of cationic dyes.