Defines methods for the determination of: - the presence of colourless chromate conversion coatings; - the presence of hexavalent chromium in colourless and coloured coatings on zinc or cadmium or aluminium-zinc (mass fraction of aluminium: 55%, within a range of 54% to 56% mass fraction) and zinc-aluminium (mass fraction of aluminium: 5%) alloys; - the total chromium content per unit area on zinc and cadmium; - the mass per unit area of both colourless and coloured coatings; - the satisfactory adhesion of chromate conversion coatings; - the quality of chromate coatings.