Redd shot most of the ghost-actors individually against bluescreen “with many, many passes of motion-control photography. We pretty much kept every ghost separate, except in a couple of cases where we had ghosts that had to interact. Those would require us to go through an elaborate roto process later on.”

Day-Glo Ghosts
Redd got a good start on making the ghost-actors appear spooky, however, via a high-tech product from the 3M Corp. Cinematographer Remi Adefarasin found Scotchlite, which is made of microscopic glass beads that reflect light. “It’s built into reflective material on freeway signs,” explains Redd. “We were able to buy the actual ink to mix into glue, and it was heavily used on props and costumes.”

Scotchlite-treated costumes designed by Mona May appeared to glow when lit with a special light mounted on the camera. “When that light shone onto the actors,” says Redd, “it would bounce right back to camera and make them look like they were glowing. If you weren’t standing next to the camera, you couldn’t see the effect.”

“The ghosts in this movie are energetic,” adds Redd, “so we wanted to create a very different look for them. We didn’t want to be Ghostbusters or The Frighteners, even though there’s beautiful work in those movies. So getting this glowing effect in-camera was really cool. My philosophy is if you can get it on set, get it!”

Rick Baker’s design for the organ player brings the ghoul to life.

Multi-Oscar-winning makeup wizard Rick Baker also played a key role in turning dozens of extras into hundreds of glowing ghosts. Through an array of masks as well as glittering makeup, Redd suggests “a wide variety of people, including Rick himself, played multiple parts. Rick and his crew are such magicians they can disguise anybody.” The masks built by Baker would later have digital effects layered on top of them by the Imageworks team.

The Layered Look
While these practical techniques provided a good foundation, completing a semi-transparent ghostly look required considerable digital treatment. The process at Imageworks began with plate stablization and tracking the ghosts into the background plates. “We used proprietary tracking software as well as Boujou and Maya,” Redd confirms. “We built tools on top of Maya to make it work really well.”

Imageworks used its optical flow software to track the movement of select points in a given image from frame to frame. This allowed them to add effects like electrical tendrils and smoke coming off the bluescreen photography of the ghosts. Redd explains that “David Stephens, our effects lead and head particle simulation guy, worked with a number of artists in coming up with a way to get these ghosts into his machine as bluescreen photography and then track their motion.

These scary specters’ transformation to finished product kept the original design intact.

“That gave us, literally, a base coat of particles that tracked around with each character. We then used that information to generate effects like smoke and electrical plasma. There were a dozen layers for each ghost running off those glows that we’d shot live.” Stephens’ prime tool for creating particle effects was Houdini, and Redd notes “he’s written tons of plug-ins for Houdini to make it work the way we wanted.”

Otherworldly 3D
Imageworks did have to create 3D-CG in order to depict one of the most famous images from the original Disney attraction: a head floating within a glowing crystal ball. For the film, the character of Madame Leota (played by Jennifer Tilly) had to be speaking while Murphy’s character walks around holding the ball.