Illusion jumps a light year or two in "Forrest Gump."
Many of the effects in the movie -- a quirky, collective-memory history of the past four decades, as seen through the eyes of a simpleton (played by Tom Hanks) -- will easily go unnoticed. These merely augmented existing visuals -- adding helicopters to the sky in Vietnam scenes, circling the Reflecting Pool in Washington with thousands of war protesters, removing unwanted minutiae from the background shots.
But the effect that will have audiences talking this summer is one in which Mr. Hanks' character is inserted seamlessly into old newsreel footage and is seen conversing and physically interacting with such luminaries as Presidents John Kennedy, Lyndon Johnson and Richard Nixon, as well as Dick Cavett and John Lennon. Primitive versions of this effect have been seen in such movies as "Zelig," and even last summer's "In the Line of Fire," but the work in "Gump" -- directed by technowonk filmmaker Robert Zemeckis -- is genuinely persuasive.
It wasn't always so.
"They always had this rough matte box version, and it always looked [ragged]," Mr. Hanks recalls. "Bob was saying, 'It's gonna look great, it's gonna be wonderful!' And I saw passes at what they were doing when I did some [sound] looping, but it was still rough, or 'puppety,' as Bob called it.
"Then, when the piece was redone, and everything was in place, I was amazed. Johnson puts the medal around Forrest Gump's head -- I was astonished. I was there, and I have no idea how they did that."
For scenes in which Mr. Hanks meets with presidents, researchers pored through hundreds of hours of newsreel footage, looking for something that approximated what was described in Eric Roth's script. (Winston Groom's novel, upon which the film is based, had his hero visit Mars at one point, but the filmmakers opted for a more earthbound, realistic Gump.)
For example, Mr. Roth originally had Gump meet Kennedy in the Rose Garden. No workable clip was located, so the action was moved to the Oval Office, where in the original footage, Kennedy was greeting Peace Corps volunteers. Mr. Roth rewrote the scene to the length specifications of the available footage.
"We looked at the footage and tried to estimate how high the camera was off the ground, and how far it was from the subject," says Ken Ralston, who at Industrial Light and Magic routinely makes the impossible possible. Mr. Ralston has served as special effects supervisor for six Zemeckis films, including "Forrest Gump," and has won two of his four Oscars for Zemeckis' films -- "Who Framed Roger Rabbit" and "Death Becomes Her."
"Then we tried to duplicate the same situation," Mr. Ralston explains. "The problem was, a lot of this footage was hand-held, and zooming in and out -- duplicating that was murder. We also had to duplicate the lighting, copying daylight with interior lighting."
"Tom studied the raw footage, and I told him, 'We're putting you right here,' " says Mr. Zemeckis. "He has a picture in his mind of what it will look like, and we have him hit very specific marks, like choreographing a dance number."
"All the scenes were shot a great many ways," recalls Mr. Hanks. For special-effects shots against a blue screen, he says, "There were very specific marks. I had to shift my gaze from different pieces of tape hanging from wires. There were different angles and a lot of repetition, but it wasn't hard, not even particularly boring. We worked at such a whip-crack pace. I'd be doing different scenes on one stage, then change costumes and run to the blue screen with the ILM guys."
Not only was Mr. Hanks placed into Kennedy's realm, but Kennedy was moved into the filmmaker's world.
"They built sets and cast the parts of the people in the newsreel footage," Mr. Hanks says. Then they had a look-alike act out the entire scene with a multi-camera setup." Kennedy was digitally placed in the Oval Office set.
"Then we took the footage to ILM and scanned it into the computer, frame by single, horrible frame," Mr. Ralston recalls. "We matched the camera movement and the placement of Tom. We would move him a few pixels left or right in the picture, which would make or break the shot -- he had to genuinely be in Kennedy's eye line. We grafted out another person. In the original footage, Kennedy was shaking hands with a woman."
The mouths of the presidents also were digitally altered so that they could recite the lines Mr. Roth had written for them and which were spoken by imitators. "These figures are so familiar -- if you put in a different mouth of a look-alike, they weren't the same characters," Mr. Ralston says. "It was painstaking work. We'd have to take mouths from other shots and other pictures of them, and put them in." Kennedy was also digitally reconstructed for the parts of shots in which Mr. Hanks passes before him.
Finally, another team would go in to make the new footage look as aged and scratchy and grainy as the newsreel footage, and add the appropriate shadows. One such sequence would take approximately eight or nine months to complete.
Effects and ethics
As fancifully as this technology is used in "Forrest Gump," the filmmakers are aware that it can be used in devastating and unethical ways in the future. For example, a politician running a smear campaign could doctor footage to make his opponent espouse unpopular or flat-out crazy viewpoints.
"We've opened up a whole new can of worms," Mr. Ralston admits. "My feeling is that this is a gentle nudge, pointing out the possibilities of a potentially horrific problem. We got the rights to the footage we used, but what's legal and what's moral doesn't necessarily mix."
Distorting previous works of film art is also something that artists'-rights groups fear -- with this technology, a movie starring Tom Cruise and Humphrey Bogart is not an impossibility. But is it right?
"If you truly believe that film is art, then you may have problems," Mr. Ralston says. "I wonder what Martin Scorsese will think when he sees Tom Hanks in footage from 'Birth of a Nation' [an ancestor of Forrest's is depicted donning the garb of a Klansman]. I hope this does open up a discussion."
"When I saw James Cagney in the Diet Coke commercial, I thought, "This is not right, I don't want to see it," Mr. Hanks says. "I don't want to see Cary Grant making goo-goo eyes at Paula Abdul. But who in their right mind would have ever imagined that this technology would ever exist? That you could create an image of a person saying something they had never said before? You can use it in an entertaining way, but politically, as well. People believe what they see. What a computer is to a typewriter, this process is to celluloid. It's a monster, and the lawyers are gonna have a field day."