HOLLYWOOD, Calif. - Before director Zack Snyder set out to reinvent history and tinker with mythology, he wanted to check with the creator himself.

In the case of 300, a ferocious retelling of the ancient Battle of Thermopylae in 480 B.C., that meant getting approval from Frank Miller, the legendary graphic novelist.

"When we first got the rights to do it, I met with Frank. We just kicked around ideas," Snyder said recently in a Beverly Hills hotel suite. "He has approval. He could have said, 'You know what, this guy? No, he's an idiot,' which I was pretty sure was what he was going to say. But, thankfully, he didn't."

Having kicked off the spring movie season Friday, the film version of Miller's 1998 graphic novel is a highly stylized affair. Snyder, an experienced TV-commercial director, made the transition to features with the grisly remake of the horror classic Dawn of the Dead in 2004. The grit and gore remain in 300, an epic sword-and-sandal battle pitting 300 greatly outnumbered Spartans (and a few hundred allies) against hundreds of thousands of invading Persians.

"The film is mythology out of history," Snyder said. "I think historians have been obsessed with taking mythology and making it real. We went the other way."

He's not too concerned about critics who say his movie departs from the historical record. When someone suggests that perhaps the Spartan soldiers who fought so valiantly wore more body armor than he depicts in 300, he counters with, "Really, so you were there?" Then he mentions that the only known statue of King Leonidas, the Spartan leader, is quite nude.

The movie doesn't match Miller's book shot for shot, but it comes pretty close.

"I would say 90 percent of the scenes in the movie are from the graphic novel. And the dialogue as well. I was really conscious of that," Snyder said.

Audiences will notice that 300 looks different from almost anything they've seen before. It exudes a lived-in look, and a grainy, orange tone dominates most scenes. The only live shot in the entire movie is a brief one of riders on horseback. Everything else was shot in front of a very large blue screen in Montreal.

Everything around the actors is digital animation, but Snyder set out from the beginning to make sure 300 didn't look like a movie "that was spit out of a computer," he said. "I wanted the movie to feel organic. I feel like the book feels dirty. Not in a sexual way - it's gritty. It has a dark quality to it. I wanted you to feel that. That's why we shot the movie on film. We actually added grain to the movie."

To Snyder, the computer-generated images are merely a tool for the director to use.

"We didn't set out to make a blue-screen movie. It just happened to be the way to do it," he said. "In that way it is liberating because it's the thing that helps me achieve the actual shot. It's restrictive only because the actors are having to understand where they are in three-dimensional space. And we don't have landmarks that really help them that much with that."

Snyder said that everything was OK once his actors started to trust the process.

"I would say: 'Don't worry. The guys are over there. This is over there. Don't get hit in the head by this guy's stick.' That worked pretty good. It doesn't take a lot of acting when someone's trying to hit you in the head with a stick. That's real."