I have twice received an office action quoting that color is not a structural element distinguishing a claim. The justification for the rejection has been In re Seid 161 F.2d 229, 73 USPQ 431 (CCPA 1947) and cited in MPEP 2144.04. In re Seid is cited for the proposition that “matters relating to ornamentation only which have no mechanical function cannot be relied upon to patentably distinguish the claimed invention from the prior art.”

In re Seid pertains to an ornamental bottle and not to color.

In the instant case, the examiner has objected to certain claims stating “claiming a color is not adding a structural limitation to the above claims.”

Contrary to the examiner’s assertion, color has been found to be a distinguishing element in a claim. See Sorensen v. International Trade Commission, 427 F.3d 1375, 1379 (Fed. Cir. 2005) stating in its relevant part:

“This reference suggests again that the first and second injection could use plastic with the same molecular structure. In that case, the ‘different characteristics’ limitation would require some difference other than molecular structure, such as color.”

“In sum, the claim language and the specification show that color differences would suffice to satisfy the broad ‘different characteristics’ limitation.” (emphasis added)
In the instant application, the applicant is asserting that color is not merely ornamental but serves a structural purpose. This has been the decision of the Court of Appeals for the Federal Circuit. Claiming color would be adding a structural limitation to the claims.