Like all good cowboys, when Robert Duvall fell off his horse, he got right back on.Preparing for “Open Range,” in which he played quiet but assertive Boss Spearman, the 73-year-old actor broke several ribs. But by the time filming began, Duvall returned to the saddle, with hat, chaps and tobacco at the ready. The role seemed to suit the actor perfectly. Soft-spoken yet to the point, Duvall gravitates toward a Western. Shortly after receiving the script for “Open Range,” the actor called director Kevin Costner and agreed to join his posse. “Ten minutes after reading it, I told him I was in,” Duvall says. Not that every Western agrees with him. He’s not particularly enamored with most of John Ford’s films and has little tolerance for pics that lack authenticity. Duvall’s career, which includes six Oscar noms and a win for “Tender Mercies,” dates back to the early 1960s. Although he was born in San Diego, Duvall owns a ranch in Virginia and comes across as a Southerner. One of his favorite filming locations is Darlington, S.C., where he co-starred in “Days of Thunder” with Tom Cruise. He prefers a director who doesn’t use too many takes. On “Open Range,” which took about 13 weeks to film in the picturesque plains of Alberta, Canada, Costner rarely shot a scene more than three or four times. “Good performances don’t come from rehearsals. That’s not the way to keep things fresh,” Duvall says. He says he’s seen Marlon Brando use up to 80 takes for a scene. The actors have worked together on “The Chase,” “The Godfather” and “Apocalypse Now,” the latter two pics helmed by Francis Ford Coppola. As to who is Duvall’s favorite director these days, Ken Loach quickly comes to mind. Duvall, who appears in a majority of big studio films but who seemingly appreciates smaller material even more, was quite impressed with “My Friend Is Joe” and the more recent “Sweet Sixteen.” “Loach listens to the actors and doesn’t watch them,” Duvall explains. If the director and actor were to ever combine their talents on a project, it certainly would be seen as a lesson in how-to’s of filmmaking.