1.1 This part of IS0 787 specifies a general method of test for comparing the colour of a coloured pigment with that of an agreed sample. 1.2 Either of the procedures described in clause 6 is aceptable but the method using an automatic muller is the reference method. NOTE - When this general method is applicable to a given pigment, only a cross-reference to it should be included in the International Standard relating to that pigment, with a note of any detailed modifications which may be needed in view of the special properties of the material in question. Only when the procedures given in this general method are not applicable to a particular material should a special method for comparison of colour be specified.