This part of ISO 23900 specifies a method of determining in polyethylene (PE) the colouristic properties of a test pigment relative to a standard, and the ease of dispersion DHPE of pigments from the differences in colour strength on dispersing colouring materials under various conditions. Method A is appropriate for use with organic powder pigments and carbon black pigments in poder form, many of which are subject to compaction (reagglomeration under pressure), for inorganic pigments in powder form and for pigment preparations in powder or flake form. Method B is appropriate for testing pigments and pigment preparations in granular form and for inorganic pigments in any form. The ease of dispersion determined in this way is valid only for the dispersion equipment, dispersión conditions and dispersion medium being used. The use of test conditions differing from those specified may give different results; this applies both to the absolute magnitude and to the relation between values of the ease of dispersion of various pigments. The subscript DHPE is therefore used to designate the value obtained as specified in this part of ISO 23900.