This International Standard specifies a method for determining the colour fastness to perspiration of leather of all kinds at all stages of processing. It applies particularly to gloving, clothing and lining leathers, as well as leather for the uppers of unlined shoes. The method uses an artificial perspiration solution to simulate the action of human perspiration. Since perspiration varies widely from one individual to the next, it is not possible to design a method with universal validity, but the alkaline artificial perspiration solution specified in this International Standard will give results corresponding to those with natural perspiration in most cases. NOTE In general, human perspiration is weakly acidic when freshly produced. Micro-organisms then cause it to change, the pH usually becoming weakly alkaline (pH 7,5 to 8,5). Alkaline perspiration has a considerably greater effect on the colour of leather than has acid perspiration. Therefore, for coloured leather, an alkaline perspiration solution is used to simulate the most demanding conditions encountered in practice.