IN "STIR of Echoes," Kevin Bacon is a regular guy from a Chicago suburb, who submits to a hypnosis session, only to learn he's part of an estimated 8 percent of the population whose subconsciousness is easily triggered by hypnotic suggestion.

Writer-director David Koepp, who came through Washington recently to promote the film (see review on Page 43), spoke of his personal satisfaction in directing this movie, his second directorial effort after 1996's "The TriggerEffect." Research was fun too. He found the idea of hypnosis so fascinating, he says, he decided to undergo a session himself.

"It was kind of intense," Koepp says. "It's like a heightened state of concentration. Unless you're part of the 8 percent, you don't black out. It's not like you don't remember. You're always there and you're always in control, unless you're one of those whose subconsciousness leaps right out. I'm from the Midwest. My subconscious is waaaay down in the basement. Packed away."

This experience was not a cinematic experience, he confesses. So he had to "fudge the scene for entertainment pleasure" by literally conveying Bacon's state of mind.

"I want you to pretend you're in a theater," says Illeana Douglas (who plays the hypnotist) in the movie. As Bacon imagines, Koepp shows us a movie screen with audience heads in the foreground. Instead of showing the actor pretending to be in a trance, says Koepp, we see what Bacon sees. And we feel as if we're being hypnotized too.

Koepp is better known in Hollywood as a scriptwriter whose credits include "Apartment Zero," "Bad Influence," both "Jurassic Park" movies, "Carlito's Way," "Snake Eyes" and "Mission: Impossible." As the director on "Stir of Echoes," he enjoyed a luxury rarely experienced by writers in Hollywood: control.

"Screenwriting is half an art form," explains Koepp, a bearded 36-year-old with an easy, witty manner. "You write it, then someone else always directs it. And no matter whether the movie ends up worse or better than what you wrote, it's always different" from the scriptwriter's original vision.

Even when you're included in discussions about the movie, Koepp continues, "you lose the arguments" with the big stars, the producers and the directors. "After a certain point, you see the director's eyes glaze over. No matter what you say, he's going to do it [his way] anyway and you can type what he wants or he can have someone else type it . . .

"The only way to be completely happy," says Koepp, semi-facetiously, "is to give up your soul."

But this time, Koepp not only typed, he won the arguments -- uh, in consultation with Bacon, who was a producer. With his soul intact, he confesses, "I was very happy on this movie."

THE SMITHSONIAN highlights Hispanic Heritage Month this weekend with a festival of 32 Latino films. The films are part of a bigger celebration of the culture that includes plays, panel discussions and a two-day Fiesta Musical Sept. 25-26 at the National Zoo.

The film festival, which features the work of Latino filmmakers working in the United States, starts off Sunday at 6 with "Luminarias," directed by Jose Luiz Valenzuela, a lighthearted look at the intertwined stories of four, modern-day successful Latinas.

The free series continues on Mondays and Tuesdays at 12:30, Saturdays and Sundays at 12:30 and 3:30, through Oct. 12. All films screen at the Hirshhorn Museum and Sculpture Garden's Ring Auditorium. For more information, call 202/357-1600. Spanish speakers can call 202/357-4577. You can also access the schedule on the internet by hitting www.npg.si.edu/cal/latino99.htm.