How does a conductor lead an orchestra in the performance of a live movie score? It’s bit like the “how do you get to Carnegie Hall?” axiom: practice, practice, practice.

“It’s all in the preparation,” said conductor Richard Kaufman, who directs many of the CSO at the Movies concerts, and who will be on the podium for two of the three series events this season: “Casablanca” (1942) on March 13 and 15 and “Jurassic Park” (1993) on May 15 and 17, as well as two non-subscription offerings, “Home Alone” (1990) on Dec. 6-8 and “Star Wars: Return of the Jedi” (1983) on June 24-27. (Justin Freer conducts the kick-off film in this year’s series, “Harry Potter and the Goblet of Fire” on Nov. 29-30 and Dec. 1.) “I’m a preparation fanatic, so when I stand in front of an orchestra, my job is to be completely prepared and to do everything I can to make the whole process as easy and fulfilling as possible for the musicians.”

CSO at the Movies programs fall into a category known in the industry as “live to picture”: musicians perform a film’s score while the complete movie is screened above the stage. The CSO introduced this kind of programming more than 25 years ago, but it took off with the launch in 2004 of Friday Night at the Movies (later renamed CSO at the Movies). Jim Fahey, director of programming for the CSO’s Symphony Center Presents, oversees the series, and with Kaufman, has shaped its evolution. “We look to feature the finest film scores that are available,” Fahey said. With its Oscar-nominated score by John Williams, ” ‘Return of the Jedi’ fits into that category,” he said. “The same goes for ‘Casablanca’ [with an Oscar-nominated score by Max Steiner].”

The live-to-picture movement has boomed in the last decade, with companies such as Film Concerts Live!, CineConcerts and John Goberman’s Symphonic Cinema among the leaders in this field. They negotiate performance rights, supervise the creation of the musicians’ sheet music, and technically make the movies stage ready. “For a film to be screened live with an orchestra, the music first needs to be removed from the soundtrack,” Kaufman said. “For older films, the original orchestra track was married to the dialogue and sound effects, and so the music must be erased wherever there is no dialogue or sound effects. Where there is music under dialogue, the music remains in the background.”

Contemporary films, Kaufman said, present fewer issues because “the score is on what’s called a music stem, and after it’s removed, you’re left with only dialogue and sound effects.”

The growth of digital technology has streamlined the performance process but these concerts still demand a conductor schooled in the art of directing live to picture. To keep the orchestra in sync with the movie, the conductor usually relies on either a click track (an in-ear metronome) or visual streamers (lines shown on a conductor’s monitor that indicate musical sync points).  Both methods originated during the early days of sound movies. “Clicks function like a metronome,” Kaufman said. “They’re essential for a dance-oriented film like ‘Singin’ in the Rain’ to maintain synchronization.” In addition, Kaufman occasionally uses a third method: a clock with a sweep hand. For silent films, “all the technology is between my ears,” Kaufman said, laughing. “You just have to know every scene of the film and hit exactly the right spots on basically every moment of the film.”

The ultimate star, Fahey and Kaufman emphasize, is the CSO itself. “The reason this series is such a success is due to the skill and brilliance of the orchestra,” Kaufman said. “It’s amazing what they have done with such incredibly complicated music, in limited rehearsal time. It’s a challenge that is met head on by the musicians and staff. Frankly, it boggles my mind how incredible they are.”

A version of this article appeared previously on Sounds and Stories.