This International Standard establishes guidelines for the sensory evaluation of the colours of products. The procedures specified are applicable to solid, semi-solid, powder and liquid products, which can be opaque, translucent, cloudy or transparent in nature, as well as matt or glossy. General information is also given about the viewing and lighting conditions to be used in various situations in sensory analysis, such as difference testing, profile analysis and grading methods, performed by panels of selected assessors or by individual experts in special situations. This International Standard does not deal with consumer testing or with assessment of the metamerism of colours of food products. NOTE 1 Metameric matches are described in Annex A. NOTE 2 Particular products can be subject to specific International Standards for their sensory analysis, e.g. ISO 3591[1], which specifies a wine-tasting glass.