There are two words Ebenezer Scrooge throws into conversation at the start of every Christmas Carol. The first is "Bah!" The second: "humbug!" Dickens used them, complete with exclamation points, on the first page of his original novella. The film-maker Robert Zemeckis makes us wait no more than a couple of minutes before inserting them into Disney's latest, hi-tech rendering of the classic seasonal parable.
Arranging to meet Zemeckis to discuss his new project, a three-dimensional film staring Jim Carrey as Scrooge and created by "performance capture," is, in its own way, something of a humbug. Endless PR people "vet" you. They issue instructions about what cinematic terms you may, and may not, use in conversation with him. They insist that all interview questions "must be focused on the film, and not his career as a whole".
This is baffling. Zemeckis is, after all, one of modern cinema's great technical innovators. In Who Framed Roger Rabbit, he successfully combined cartoon and traditional live-action footage. In Beowulf and The Polar Express, he helped popularise performance capture. A Christmas Carol revisits these creative footsteps. How, therefore, could we possibly discuss it without considering his "career as a whole"?
Eventually, he agrees to an audience. It happens at the Four Seasons hotel in Beverly Hills. Just before kick-off, I get an emailed instruction that Mr Zemeckis would like me to refer to his cast as "actors" rather than "voices" during our coming conversation. When we meet, however, he seems perfectly charming, if a touch nervous.
We talk about A Christmas Carol, which, aside from Carrey, has a mostly British cast including Gary Oldman, Colin Firth and Bob Hoskins. The film marks Hollywood's umpteenth "go" at the Scrooge story. Most of its predecessors are pretty good. Mickey Mouse's 1983 Carol was splendidly subversive. The Muppets one, in 1992, was archly satirical. It is, in other words, a tale that seems to adapt well. Why?
"Charles Dickens wrote a book that has got everything that a kid would want in a movie in it," he ventures. "It has ghosts, Christmas, a narrative that is easily understandable and universal. And the original book is beautifully written and wonderfully surreal. I was seven when I first read, and I've been in love with the story, and wanted to make a movie of it, ever since."
The Zemeckis Carol that premieres in London tonight, is beautifully presented, efficiently paced, and joyfully performed. Carrey is, after several years of hit-and-miss, back to something like his best. Purists will note that, of all the Christmas Carols made over the years, it's probably the one that most closely resembles the original text.
Its rendering of Victorian London is also striking: atmospheric (especially in 3D), and geographically correct, it neatly avoids "Disney-fying" the grinding poverty and social deprivation that Dickens sought to portray. Before filming, Zemeckis, in typically meticulous fashion, spent several days on guided tours of our capital city, visiting museums to ensure that his film would withstand a historian's scrutiny.
"If you've ever been on a Dickens tour, they take you to the modern buildings in the city. You'll be looking at, say, a giant glass office and they'll say, 'This is where the church tower was that we think inspired Dickens to write about a gothic church.' It's important to go there and see it, because he did write from experience."
From the start of his career, which hit the big time in 1985 with Back to the Future, his films have been marked by an attention to detail and historical integrity. Forrest Gump, his most successful film, which garnered a Best Director Oscar, is an enlightening romp through 20th-century US current affairs.
Zemeckis, 57, has another great obsession: state-of-the-art film-making techniques. Though dressed in Californian leisure kit of jeans and an open-necked shirt, he has the look of a man who has always spends plenty of time at a computer screen. His later Back to the Future films popularised "match-moving", essentially sticking computer graphics into live action Roger Rabbit was one big, expensive visual experiment.
More recently, he's become intrigued by performance capture. This is the form of film-making that requires actors to dress up in computerised jumpsuits that record their every move and facial gesture. An elaborate computer then turns those movements into an animation. A Christmas Carol will, he hopes, go down in history as the first film that really exploits the possibilities of the technology to something like their full potential.
To this end, individual actors play several different characters in the film. Sometimes, they represent separate characters who appear in the same scene. Jim Carrey, for example, has seven parts. He plays Scrooge at four completely different stages of life, together with the exotically rendered ghosts of Christmas past, present and future.
On one hand, this lowers the cost of a production (the entire cast of A Christmas Carol, which has many crowd scenes, is just 15 people strong). On another, Zemeckis contends, rightly, that it makes for a pleasingly reflective version of the story. "Dickens intended each of the ghosts to be alter egos of Scrooge," says Zemeckis. "With performance capture, they really can. The ghosts are played by Jim, like Scrooge is."
To an actor, the novelty of the medium has its own appeal, he adds. "Actors love the challenge of doing several roles. If you were to go to someone like Gary Oldman, and say, 'We are doing a live action version of A Christmas Carol and we'd like you to play Cratchit,' he'd probably say no. But we offered him the chance to play both Cratchit and Marley, and his response was, 'I've got something meaty, it'll be fun.'"
The other, less immediately obvious virtue of performance capture is creative freedom. Live action movie-making, Zemeckis says, is always compromised by the demands of camera crews. Actors are constantly chopping and changing, filming tiny segments that are then woven into the tapestry of a finished film. In a performance-capture production, they are free to experiment, at length.
"In traditional movie-making, you can be doing a shot, and an actor does something brilliant. You don't even know where it came from. And the camera operator will say, 'Sorry, it wasn't in focus.' Then you want to kill yourself, because the actor can't get that moment back, however hard he tries. The way we made A Christmas Carol, we didn't have that problem because everything they do is recorded."
That sentiment is widely echoed by the cast. Colin Firth describes playing Scrooge's nephew, Fred, as the "easiest job" he's ever had. The various scenes he appeared in, which in a live-action movie would have taken weeks to produce, were instead filmed in just two days, in London.
"It was the first time I've done performance capture, and it was over so quickly, because we could get everything we wanted in that time," he says. "It's peculiar: you are utterly free, from beginning to end, to play a scene without any of the usual things holding you back."
My own suspicion is that performance capture is that it also appeals to the perfectionist in Robert Zemeckis. At one point in our talk, he describes it as a "wonderful medium for someone who likes to have control over his cinema". It lets him work with actors on an intensive, one-on-one basis, knowing that he can later spend as long as he likes fine-tuning their performance in the computerised editing suite.
"He's like this enormous grasshopper" is how Bob Hoskins, who plays a couple of the older characters, puts it. "Always reminds me of one. He's got great big long legs, big feet sticking out, and this big enthusiasm. He'll stand up and run around the set saying, 'Why don't you try this?' And he's got such good ideas. He's like one of those kids that you hated at school, because they were too bright."
At its best, this gives the performances in A Christmas Carol a pleasing sense of anarchy. Like any great director, Zemeckis is nothing if not obsessive, a trait that he traces back to his Catholic childhood in 1950s Chicago. He once blamed his workaholism for the breakdown of his first marriage, to actress Mary Ellen Trainor. The film, therefore, has been endlessly tweaked and improved. Its final version boasts flawless theatrical timing. There are moments that make grown men spill popcorn. It may even – to the dismay of Disney bean counters – be a touch on the scary side for younger children.
Are there any other problems? Zemeckis admits that he sometimes misses the "happy accidents" that occur shooting live action. "There are times on location, when you say, 'Oh my god, look at that beautiful tree,'" he says. "That happened to us on Forrest Gump, I found that beautiful oak and I said, 'That's where we're going to have Jenny's grave.' With A Christmas Carol, we created the scenery from our imagination. We were the painters, so we didn't get those sort accidents."
But when talking about his pet project, Zemeckis prefers to look firmly on the bright side. Performance capture, he strongly believes, is the cinema of the future. To think anything else, he wants you to believe, would be a perfect example of what Ebenezer Scrooge might call humbug.
'A Christmas Carol' opens nationwide on 6 November