When testing paints, varnishes and similar coatings, their properties or any changes to them frequently cannot be described in terms of measured values, but must instead be assessed subjectively. This specifies a standardized rating scheme on which to base assessments, with the purpose of facilitating evaluation and promoting mutual understanding. This rating scheme shall only be used where the results of tests cannot be expressed in terms of direct measurements and here are no available standards dealing with the evaluation of the properties concerned, e.g. those with special parameters (see the "Other relevant standards" clause on page 3).