* What: “Behind the Screen: Making Motion Pictures and Television”

* Where: Exploratorium, Palace of Fine Arts, 3601 Lyons St., San Francisco

* When: Through May 13. 10 a.m.-5 p.m. Tuesdays and Thursdays- Sundays, 10 a.m.-9 p.m. Wednesdays

* How much: $9 general; $7 university students, ages 65 and older; $5 disabled, ages 6-17; $2.50 ages 3-5; free for ages 2 and under, members and first Wednesdays.

* Call: 415-397-5673,


Unless otherwise indicated, all events take place 2 p.m. at the McBean Theater.

* TODAY: The documentary “Color Adjustment” (1991), part of “Films on Image and Race, by Marlon Riggs”

* SUNDAY: The documentary “Ethnic Notions” (1987)

* MARCH 3: “From Imagination to Image,” with guest Chuck Workman

* MARCH 24 and 25: “Sound Effects: The Magic of Foley” with a guest Foley artist

* APRIL 4: “The Art of Anime,” 7 p.m.

* APRIL 7. “The Making of When the Spirit Moves'” (1999)

* APRIL 8: “For the Love of It: Films From Amateur Film Clubs of America”

* APRIL 22 and 23: Early Animation series, “Before Mickey” (1982)

* MAY 5: Hollywood makeup artist will turn a volunteer into an alien. Noon to 4 p.m. Location TBA.

Two raptors bare their jagged teeth as they close in on their prey. The would-be snacks, young Tim and Lex, scrabble about terrified as they seek a hiding place in the stainless-steel kitchen. Tim freezes with fright as he hears a raptor just around the counter. One peek around the corner, and surely the raptor will see and devour him.

“Meow!” the raptor says thunderously.


That’s what happens when you get too many editors in the same film studio. The scene is from “Jurassic Park,” but the sound effect is just one of many offered to an experimental film editor, courtesy of the Exploratorium exhibit, “Behind the Screen: Making Motion Pictures and Television.”

If visitors tire of plugging in flatulent-sounding noises for gunfire as Arnold Schwarzenegger rattles off a round of bullets in “Terminator 2: Judgment Day,” they can voice-dub scenes in “Jerry Maguire,” lay down a soundtrack, edit a wide-screen picture for television or give a weather forecast while ducking airplanes (courtesy of computer imagery).

That people love uncovering the magic of movies is evident: Attendance to the science center has jumped up 20 percent since the Feb. 10 opening weekend. On loan from the American Museum of the Moving Image in New York, the exhibit which runs through May 13 reveals the technology but doesn’t diminish the illusion of moviemaking.

“Behind the Screen” goes back to cinema’s beginning and before, when people experimented with early moving images. The equipment on display often employs concepts as simple as flipping a pad of paper, each drawn with slightly different figures. One is a zoetrope: Touted as a toy, it resembles a perforated drum with drawings in its interior. Peek through any holes, start spinning the zoetrope and suddenly the drawings merge into a moving figure.

Other displays include costuming and makeup, with the likes of Yoda and Chewbacca making a special visit from the Empire. Those intrigued with exploring possible career options, or those merely interested in interpreting the credits, job descriptions are given for everything from Best Boy to Gaffer.

As keeping with the Exploratorium principles, the science explained concentrates not so much on filmmaking technology but on the perceptions of the body to the technology. The concept of visual persistence, for instance, explains how people can perceive motion in a movie: Say you’re looking closely at a film reel of the seconds hand of a clock sweeping around. The first frame shows the seconds hand at 12, the next frame shows the second hand at 1.

Although there aren’t images of the seconds hand between 12 and 1, when you play the film, the first image will linger in the eye long enough for the second image to catch up visual persistence. Our minds fill in the missing gap between these discrete images. The gap can’t be too big: If one frame featured the second hand at 12 and the next one at 4, then there would be a perceptible blip.

On weekends, “Behind the Screen” features classic shows and special guests. This weekend, the focus is on “Films on Image and Race, by Marlon Riggs.” Riggs, a filmmaker and UC Berkeley Graduate School of Journalism professor who died in 1994 at age 37, made intelligent, probing documentaries on sensitive subjects from media depictions of race to homosexuality. The McBean Theater screens “Color Adjustment” 2 p.m. today and “Ethnic Notions” 2 p.m. Sunday.