Erotic films usually contain nudity, and nudity in a sexual context is common in pornographic films. A film on naturism or about people for whom nudity is common may contain non-sexual nudity, and some other non-pornographic films may contain very brief nude scenes. The vast majority of nudity in film is found in pornographic films. Nudity in film has since the development of the medium been controversial, and most nude scenes in films have had to be justified as being part of the story, in the concept of artistically justifiable nudity. In some cases nudity is itself the object of a film or is used in the development of the character of the subject. In some cases, nudity has been criticized as superfluous or gratuitous to the plot, and some film producers have been accused of including nudity in a film to appeal to certain audiences. Many actors and actresses have appeared nude, or exposing parts of their bodies or dressed in ways considered provocative by contemporary standards at some point in their careers.