Key credits: “Amores perros,” “Frida,” “21 Grams”Awards: Golden Frog at Camerimage for “Amores perros” Connection: Prieto was in Thailand winding up shooting “Alexander” for director Oliver Stone. “I remember I was in a car and Ang Lee, who I’d never talked to before, called and described the storyline for ‘Brokeback Mountain,'” says the Mexican-born cinematographer. Lee was an admirer of “Amores perros” and knew its director, Alejandro Gonzalez Inarritu. A script was immediately sent over to the d.p. in Thailand. “As soon as I read it, I knew I had to be a part of this project.” Straight from finishing up “Alexander” he went right to Canada to start work on “Brokeback.” Equipment: Arricams outfitted with Cooke S4 lenses; Kodak 5246 film stock for the small-town scenes, and 5245 for the daylight mountain scenes “because its clean grain let us capture the transparency of the air,” he says. Kodak 5279, with more contrast and color saturation, was used for the Texas settings; and 5218, a fast film, for the moonlit tent scene. “It not only looks dark on the screen but I wanted it to be very dark for the actors, really hidden, because intimacy on the set was important,” says Prieto. “Even though the film stock was fast, I was underexposing and had the lens wide open.” Challenge: The weather for the outdoor scenes shot in the Canadian Rockies “was very unpredictable and at times things became stressful,” he notes. “The area around Calgary has those beautiful, deep-blue skies with very interesting cloud patterns, but the clouds are constantly moving past the sun, so it’s clear, and then it’s cloudy, and then it’s clear again.” Setback and solution: Early in pre-production it snowed, so Heath Ledger and Michelle Williams, as Ennis and his wife Alma, were asked to do the scene where they go down a hill on a sled. “On take two the sled flipped, and Michelle really sprained her ankle and had to go to the hospital,” he recalls. “We were only on our third day and we temporarily lost our main actress — so we had to reschedule.” Creative mantra: For Prieto, his first read-through of the script is very important. “I go back to that a lot, to my first impressions, my first emotions — that’s where it all begins,” he says. When he meets with the director on a film for the first discussion, he mainly listens to his or her ideas and approach. But after that, “I like to propose a lot, to bring ideas to the table. I maybe go beyond what some people think is the job of the cinematographer. But I try not to limit my comments to lighting and lenses and camerawork.” Upcoming: Prieto just finished lensing another feature for Gonzalez Inarritu, “Babel,” shot in several countries including Morocco, Mexico and Japan. The film, he says, can be seen as the capstone to a trilogy that began with “Amores perros” and “21 Grams.” He’s now reviewing scripts for his next project.