This issue was addressed by the World Trade Organization Agreement on Trade-Related Aspects of Intellectual Property Rights[1], which broadened the legal definition of trademark to encompass "any sign...capable of distinguishing the goods or services of one undertaking from those of other undertakings" (article 15(1)).
the applicant seeking registration of a hologram must submit a drawing of the mark that captures the dimensions thereof.
Further, Examiners are instructed to refuse registration of any holograms that show two different images on the grounds that the application is seeking protection for two separate marks.
In Sieckmann v German Patent Office (case C-273/00) [2] the EcJ states that graphical representation, preferably means by images, lines or characters, and that the representation must be clear, precise, self-contained, easily accessible, intelligible, durable and objective.
This definition generally encompasses only very simply structured holograms, and therefore an applicant for a CTM may use one photograph or some views to graphically represent their trade mark, see first external link.