Heh, years ago a judge at a local art show made a statement to the effect "the frame should be invisible." That is, it should not distract from the artwork. Of course, a few days later I saw an exhibit of work from the collection of a local museum that had an oil painting about 30 x 40 inches in a presumably original frame. The frame "moulding" was about 10 or 12 inches wide and covered with carving on top of carving -- and gilded -- different people and different eras had different ideas.