This part of ISO 787 specifies a general test method for comparing the colour, in full-shade systems, of white, black or coloured pigments with that of an agreed reference pigment, using a colorimetric procedure. NOTE 1 When the general method specified in this part of ISO 787 is applicable to a given pigment, only a cross-reference to ISO 787-25 needs to be included in the International Standard giving the specification for that pigment, indicating any detailed modification that may be needed in view of the special properties of the material in question. Only when the general method in this part of ISO 787 is not applicable to a particular material is a different photometric method for comparison of colour to be specified. ISO 787-1:1982, General methods of test for pigments and extenders — Part 1: Comparison of colour of pigments, describes a general test method for visual comparison of the colour of pigments.