This paper explores the relationship between written standards and the phenomena under standardisation. In this paper written standards are looked upon as representations of practice phenomena, and the paper argues that standards can represent these to a smaller or larger extent. Therefore, some written standards may open up for the creation of illusions. These are created when written standards' content is not in accordance with the perception standard adopters and standard users have of the specific practice phenomenon's content. This general theoretical argument is exemplified by the specific case of organic agricultural standards.