LOS ANGELES — The movie industry is trying a new approach to stop people from downloading pirated copies of films over the Internet: It's asking them nicely.

Movie studios were launching a campaign Tuesday with television ads and in-theater spots featuring makeup artists, set painters and other crafts people saying that piracy robs them of a living.

The Motion Picture Association of America has also developed a curriculum on copyrights for use in classrooms by Junior Achievement. The "Digital Citizenship" program covers the history of copyright and culminates with a nationwide contest in which students suggest ways to persuade peers that swapping copies of music and movies is not only illegal, but unethical.

"What we are endeavoring to do is both communicate that it's wrong and also communicate that there are human stakes and that those stakes are not just millionaires making less millions," said Peter Chernin, president and chief operating officer of News Corp., whose Twentieth Century Fox studio made the spots.

The film and music industries have recently become more aggressive in enforcing their copyrights in the courts as well as lobbying for tougher laws to punish violators.

While copies of popular blockbusters can be found on the Internet, sometimes days before the movie is released to theaters, computer copies of films are still too large to easily download and are often poor quality copies made using hand-held camcorders.

Music files, by contrast, are smaller and are CD quality, making them easy to share.

Movie studios believe they still have a few years before Internet connections become fast enough to threaten them in the same way. Studios are experimenting with new business models, including making films available legitimately online.

But studios will succeed only if they move quickly to offer legitimate alternatives that consumers want, analysts say.

"It may just be that consumers aren't quite ready yet to turn to the Internet for movies," said Fred von Lohmann, a lawyer for the Electronic Frontier Foundation. "But when they are, the answer will be to offer them a compelling legitimate alternative, not telling them to behave themselves."

The industry's 30-second television ad will have its first run Thursday night on all the broadcast networks and most cable channels during their first prime time break, sometime after 8 p.m. The first of several trailers will begin running Friday in most major theater chains nationwide.

The first trailer features David Goldstein, a set painter. Each ad ends with the tag line, "Movies. They're worth it."

The campaign will also include a Web site that outlines the moral implications of illegal downloading as well as the legal and practical consequences.