Functional color
Color Matters examines four legal battles over color trademark infringement in packaging and branding, each decided by a test of "color functionality."
The U.S. courts denied Ambrit's request for protection of blue, on the basis that royal blue when used to package frozen desserts was functional and could not be monopolized in a trademark. The ruling stated "Royal blue is a 'cool color;' it is suggestive of coldness and used by a multitude of ice cream and frozen dessert producers." Although the ruling acknowledged the issue of protecting the consumer from confusion, preventing a monopoly of a functional color was a greater issue.
(via CG Explorer)