Magic Behind ‘Casper’ : Universal Studios Hollywood opens an exhibit today that demystifies some of the film’s ghostly special effects.

At the heart of the new film “Casper” lies a simple romance between the boyish, translucent hero and a teen-age girl who moves into his haunted mansion.

But putting that simple story onto the screen--making a movie in which animated ghosts cavort with human actors--proved to be a complex endeavor, requiring the equivalent of 19 million floppy disks of computer-generated images.

That’s the story Universal Studios Hollywood has attempted to tell with its “Casper--Behind the Screams” exhibit, which opens today, along with the movie, and runs through Labor Day.

“We pride ourselves on taking guests behind the scenes,” said Don Burgess, who produced the exhibit at the Universal City theme park. “We’ll let them see how the ghost effects were done and see the props and the costumes.”

The film’s setting, the haunted Whipstaff Manor, has been partially reproduced to house the exhibit. The first room offers a re-creation of the dusty, prop-filled attic. Guests pass by mirrors that make it appear as if Casper is hovering nearby.

Farther along, there are miniaturized versions of the mansion’s grand hall and kitchen--stunningly exact models that were used to film some of the movie’s sequences.

But the most interesting portions of the exhibit are shown on video screens. The film’s producers have dissected two animated scenes, explaining some of their special-effects magic.

“Audiences are getting more and more sophisticated,” said Marvin Levy, a marketing consultant for Steven Spielberg’s Amblin Entertainment, which produced the movie. “People see the film and ask, ‘How did they do that?’ Then we show them a little bit.”

In one scene, Casper hands his teen-age love, played by Christina Ricci, a glass of orange juice. The exhibit shows unedited film of Ricci taking the glass from the end of a long pole. Animators then use computers to erase the pole and its shadow. Additional computer images track Ricci’s eye movements so that, when Casper is added, he remains always in her gaze.

*

This technology, called CGI for computer-generated imaging, was used to create the dinosaurs of “Jurassic Park.” But when the Universal Studios tour mounted a behind-the-scenes exhibit for that movie last summer, Amblin did not allow any glimpses of CGI.

“The technology was still too new,” Burgess said.

In fact, CGI was used in only 40 shots during “Jurassic Park.” In “Casper,” the friendly ghost and his three spectral uncles appear in far more scenes, requiring approximately 250 CGI sequences.

Special-effects artists spent two years on the project, altering many scenes frame by frame. As the exhibit shows, a 90-second chat between Casper and Ricci took eight months to create.

This movie minutiae is draped in curtains and lighted by chandeliers, all props from the original sets. Other displays show how costumers aged actor Eric Idle’s clothing as he goes through a series of pratfalls. There are explanations of set construction and matte photography, too.

But not all of the wizardry is given away. Some special effects would require lengthy technical explanations, Levy said.

Besides, he said, “we want to keep a little bit of the mystery and the fun.”

(BEGIN TEXT OF INFOBOX / INFOGRAPHIC)

WHERE AND WHEN

What: New “Casper” attraction.

Location: Universal Studios Hollywood, Hollywood Freeway at Lankershim Boulevard, Universal City.

Hours: 9 a.m. to 7 p.m. daily.

Price: $31 general, $24.95 children 3 to 11 and seniors 60 and older. Through June 16, special admission for California residents, $23.

Call: (818) 508-9600.