by Lee Yanowitch, Reuters, Saturday May 22, 1:12 AM ET

CANNES, France (Reuters) - Putting aside for once his taste for the bizarre and the violent, director David Lynch has turned his camera lens to the true story of an old man's trip on a lawn mower to see his ailing brother.

Viewers at the screening of "The Straight Story" at the Cannes Film Festival on Friday gave a standing ovation to this luminous Golden Palm entry about forgiveness.

The film traces 73-year-old Alvin Straight's six-week trip across Iowa and into Wisconsin in 1994 aboard a run-down riding mower whose top speed was four miles per hour.

Straight is searching for forgiveness after a falling out with his brother Lyle. The rupture came after he took to drinking after serving in combat in France during World War II.

"I think you've got to dig deep to do what Alvin did. He had to be stubborn, had to get over a lot of obstacles to prove to his brother he cared for him," Lynch said told a news conference in his Midwestern drawl.

Unlike his past films, "The Straight Story" carries a G rating, designating it as acceptable for viewers of all ages. Lynch's previous films are far more restrictively rated.

"A gentleman named Tony called me up and said you've got a G rating. And I said, 'You gotta tell me again because it's the last time in my life I'll hear that'," Lynch, who won the Palm in 1990 for "Wild at Heart," said.

Richard Farnsworth, who gave a stunning performance as Straight, was for decades a stuntman for directors like John Ford, Howard Hawks and Sam Peckinpah before he got his first major speaking role in 1977.

He wielded a sword in Stanley Kubrick's "Spartacus" and drove chariots in Cecile B. DeMille's "The 10 Commandments."

"Sometimes people are born to play a role," Lynch said of Farnsworth, whose extraordinary eyes were at the heart of his portrayal.

Screenwriters Mary Sweeney and John Roach, who first read about Straight's trip in the New York Times, said they talked with his family and checked his military records to research the film.

"Then we followed the route he took and talked to people who met him and that gave the film its richness," Roach said.

Golden Iowa cornfields, sunsets over the flat horizon and the lush green valleys of Wisconsin were exquisitely rendered by cinematographer Freddie Francis.

The film is slow-paced and calm, but unlike several other Golden Palm candidates this year, it never plods.

Harry Dean Stanton plays Lyle, who utters his only two lines when Straight finds him in a run-down shack in the final poignant scene.