A method suitable for use in small trade stores or retail shops for assisting in providing the correct color or coating compositions mixed in the store or shop in which colorants (II) are added to a base paint (2), the base paint (2) being provided in a lidded container (I). The base paint (2) is pre dispensed in a lidded container (I), thereby avoiding the need to weigh it accurately in store thus saving time. Further time is saved by adding the colorants simultaneously to the base paint (2). The actual load (usually the combined weight of the can and the contents) is compared to the correct load stored in a database and the operator is alerted if the two fail to match.