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)).
Requirements are set out in the Trade Marks Office Manual of Practice and Procedure issued by IP Australia.
In Libertel Groep v Benelux Merkenbureau (case C-104/01)[2] dated May 6, 2003 the ECJ repeats the criteria from Sieckmann v German Patent Office (case C-273/00)[3] 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.
However, an applicant's ability to register colour trade marks is limited by several considerations, in line with European Union jurisprudence.
In Saint-Gobain Corp. v. 3M Co., the purple colour was considered functional for coated abrasives, because “[i]n the field of coated abrasives, color serves a myriad of functions, including color coding, and the need to color code lends support for the basic finding that color, including purple, is functional in the field of coated abrasives having paper or cloth backing.”[8] The Trademark Trial and Appeal Board, in In re Ferris Corp., held that the colour pink for wound dressings was functional and not registrable, as its colour resembles human skin and was selected for this specific purpose.
"Even though there is no direct function for the colour black in this case, protection was denied under the argument that consumers prefer it for aesthetic purposes.
Although the John Deere green colour does not provide any specific function to the good to which it is applied, the United States District Court for S.D.