AATCC 131-2019 is intended for assessing the resistance of the color of textiles of all kinds and in all forms to the action of steam pleating process. The materials are not pleated during the test, and it is emphasized that the test is not intended for assessing the quality of the pleating process. Three tests differing in severity are provided; one or more of them may be used depending on the requirements. The severe test is intended primarily for wholly manufactured textile such as those made from polyamide and polyester fibers. It should not be used for textiles containing wool. A specimen of the textile in contact with specified undyed cloths is steamed under specific conditions of pressure and time and then dried. The change in color of the specimen and the staining of the undyed cloths are assessed with standard gray scales.