Insightful Score Runs Through It : Music: Isham’s intuition helped him write ‘River’ soundtrack. A version will be played tonight.

When director Robert Redford showed soundtrack composer Mark Isham a cut of his film, “A River Runs Through It,” Isham said he knew intuitively what kind of score the movie needed.

A good thing, too, since because of other commitments, Isham had only a month to write the score, have it copied and record it.

“Some days, I wrote for 16 hours,” said Isham, 42. He has composed more than 20 soundtracks for films including Robert Altman’s “Short Cuts,” Howard Franklin’s “Public Eye” and Alan Rudolph’s “The Moderns” and “Trouble in Mind.”

Recently, Isham was asked by the Pacific Symphony’s principal pops conductor Richard Kaufman to create a reduction of that score for a symphonic suite. The result will be performed tonight through Sunday at the Orange County Performing Arts Center on a pops program headlined by John Denver.

Again, Isham was able to quickly solve what might have proved to be a tricky problem. The composer put a recording of the soundtrack into a digital editing device and started moving various parts of score around, seeing what worked. He found himself focusing on a few of the seven or eight essential themes. “I touched on four or five themes. The beginning of the suite starts like the beginning of the film,” where lyrical orchestral music plays under the opening credits, Isham said.

“Then we go right to the end of the film and pick up the last fishing scene, where the younger brother is swept away by some rapids.” For that scene, Isham used repetitive piano statements to create tension. “Later I used a theme that accompanies the last reading by the narrator,” which is delivered in the film by Redford.

Isham felt that “A River Runs Through It” called for a traditional score, using a full orchestra. The story, based on an autobiographical novella by writer Norman McLean, is set in rural Montana and concerns the two sons of a Presbyterian minister, who also is a devoted fly-fisherman.

“It would be acoustic, and very melodic, and it would have a hint of Celtic flavor, a folk flavor that the story hints at,” said Isham of the score. “The picture had a sense of beauty about it, the way it looked, the writing, that I felt I had to get into this music. Fortunately, I have an affinity for Celtic music, having played for six years with Van Morrison, and music that has simplicity.”

The composer, also known for his jazz trumpet work, wrote 60 minutes worth of film music for “A River Runs Through It,” which was nominated for a 1992 Academy Award.

Isham said the music for “A River Runs Through It” is not his usual fare. “I tend to be more of textural composer for film, using different types of instruments,” he said. “I have often used electronic music, and don’t get so immersed in melodic, thematic writing. My writing is more sound as sculpture, using building blocks of sound to create certain effects. That’s my philosophy of composition. But that wouldn’t make any sense in this film.”

Self-taught as a composer, Isham wrote his first score for a feature in 1984 for Gillian Armstrong’s “Mrs. Soffel.” He’s currently set to do three more films, including Redford’s “Quiz Show,” about the quiz show scandals of the 1950s.

As much as he loves writing, he also cherishes playing, and leads a quartet regularly at various Los Angeles nightspots.

“Film is collaborative,” said Isham, who lives in Benedict Canyon with his wife, Donna, and their two young sons, Jake and Nicholas. “I’m never the boss. But with my band, I get to experience a creative form where the final buck stops with me.”

* Mark Isham’s suite from “A River Runs Through It” will be played by the Pacific Symphony on a pops concert also featuring singer John Denver tonight at 8, Saturday at 3:30 p.m. and Sunday at 8 p.m. at the Orange County Performing Arts Center, 600 Town Center Drive, Costa Mesa. $22 to $50. (714) 755-5799.