We extend Becker’s conception of art worlds to articulate the boundaries which enable and constrain innovation in art. Synthesizing network and institutional approaches to art innovation, we argue that new conventions develop through a cooperative process involving mainstreamers, mavericks, outsiders, and novices – whose interactions produce novel ways of linking artists to those who consume their products. We emphasize the role of amphibious artists in bridging mainstream and maverick social types, thereby reducing the distance between ‘outside’ and ‘inside’, and crossing the more permeable boundaries separating them. We illustrate the framework with a case of innovation in the film art world: the mainstreaming of American independent cinema.