Viggo Mortensen, left, and Kodi Smit-McPhee in ‘‘The Road,’’ based on a Cormac McCarthy novel.

By CHARLES McGRATH

ERIE, Pennsylvania - Cormac Mc- Carthy’s Pulitzer Prize-winning novel, “The Road,” takes place in a world that, because of some unexplained catastrophe, has nearly ended. The sky is gray, the rivers are black, and color is just a memory. The landscape is covered in ash. The roads are littered with corpses either charred or melted, their dreams, Mr. Mc- Carthy writes, “ensepulchred within their crozzled hearts.”
For the crew that has just finished filming the movie version of “The Road” - a joint production of 2929 and Bob Weinstein’s Dimension Films, set to open in the United States in November - that meant an upending of the usual rules of making a movie on location. Bad weather was good and good weather bad. “A little fog, a little drizzle - those are the good days,” Mark Forker, the movie’s director of special effects, remarked one morning in late April while the crew was shooting some of the final scenes in the book on a stretch of scraggly duneland by the shore of Lake Erie here. “Today is a bad day,” he added, shaking his head and squinting.
“The Road” began filming in late February, mostly in and around Pittsburgh, Pennsylvania, with a later stop in New Orleans and a postproduction visit planned to Mount St. Helens, in Washington State. The producers chose Pennsylvania, one of them, Nick Wechsler, explained, because it’s one of the many states that give tax breaks and rebates to film companies and, not incidentally, because it offered such a pleasing array of post-apocalyptic scenery: deserted coalfields, windswept dunes, run-down parts of Pittsburgh.
The script for “The Road,” by Joe Penhall, is for the most part extremely faithful to Mr. McCarthy’s story of a father and son traveling alone through this blighted landscape and trying to keep alive the idea of goodness and civilization - the fire, they call it. The script does enlarge and develop in flashback the role of the man’s wife (played by Charlize Theron), who disappears quite early from the novel, choosing suicide rather than what she imagines will be starvation or worse. And of course the script lacks Mr. McCarthy’s heightened, almost biblical narrative style.
Some of that could be suggested by the look of the film, said the director, John Hillcoat, but mostly the nature of the bond between the man and the son, who in the script, as in the book, speak to each other in brief, freighted moments, would have to come out in the performances.
Viggo Mortensen, who plays the father, said the same thing. “It’s a love story that’s also an endurance contest,” he explained, and quickly added: “I mean that in a positive way. They’re on this difficult journey, and the father is basically learning from the son. So if the father-son thing doesn’t work, then the movie doesn’t work. The rest of it wouldn’t matter. It would never be more than a pretty good movie. But with Kodi in it, it has a chance to be an extremely good movie, maybe even a great one.”
Kodi is Kodi Smit-McPhee, an 11-yearold Australian who plays the son and stunned everyone when he tested for the part. Some of the crew privately referred to him as the Alien because of the uncanny way that on a moment’s notice he switched accents and turned himself from a child into a movie star.
In the novel the father and son have a relationship that is both tender and businesslike; they’re trying to survive against great odds, after all, and there isn’t much time for small talk. Both on and off the set Mr. Mortensen and his co-star behaved much the same way.
For a scene in which the father, carrying the son on his shoulder, chases down a sandy road after a man who has stolen their belongings, Mr. Mortensen did wind sprints and jogged in place to make himself seem breathless and exhausted. Kodi simply turned limp on cue, and Mr. Mortensen snatched him up like a sack.
The next scene - in which the father and son catch up to the thief, and the father forces the man to take off his clothes, leaving him naked and freezing - took forever to set up. The crew members erected a canopy over the road to cast an end-of-the-world shadow, and a while later, when the sun had moved, they had to reposition it.
The rest of the day ticked by slowly, in a way that was a reminder that filmmaking may be the last vestige of 19th-century artisanal labor: hours and hours to capture what on screen would last just a few minutes.
“It was hard to get a rhythm out there today because of the sun,” Mr. Mortensen said on the way back to his trailer. “But Kodi was unflappable, as usual. I don’t even think of him as a kid. There are things he’s done on this movie that I’ve never seen anybody do before. And there are many adult actors who never have a moment like he has every day. I can’t say I’ve ever worked with a better partner.”