This part of ISO 10545 describes a method for utilizing colour measuring instruments for quantifying the small colour differences between plain coloured ceramic tiles, which are designed to be of uniform and consistent colour. It permits the specification of a maximum acceptable value, which depends only on the closeness of match and not on the nature of the colour difference. This part of ISO 10545 is not applicable to colour variations produced for artistic purposes. NOTE This test is applicable only when small colour differences between plain coloured tiles are important in a specification or by agreement.