This part of ISO 1833 specifies a method, using dimethylformamide, to determine the percentage of acrylic, modacrylic, chlorofibre or elastane, after removal of non-fibrous matter, in textiles made of binary mixtures of - acrylic, certain modacrylics, certain chlorofibres, certain elastanes and - animal fibres, cotton (scoured, kiered or bleached), viscose, cupro, modal, polyamide, polyester or glass fibres. It is applicable to animal hair, wool and silk dyed with pre-metallized dyes, but not to those dyed with after-chrome dyes.