This part of IS0 787 specifies a general method of test for comparing the heat stability of the pigment under test against that of an agreed sample. 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 modification which may be needed in view of the special properties of the pigment in question. Only when this general method is not applicable to a particular pigment should a special method for comparison of heat stability be specified.