Two summers ago, shortly after the American Film Institute arrived at the newly restored Silver Theater in Silver Spring, entertainer Harry Belafonte took part in one of its programs. It fell to theater director Murray Horwitz to take the star out to dinner.

As they passed a group of women dining al fresco, one jumped to her feet. "Harry Belafonte!" she said, according to Horwitz. "In Silver Spring!"

The woman's exuberance, Horwitz said, was evidence that the AFI Silver Theater and Cultural Center was going to do something positive for the area. Yesterday, along with lead sponsor Discovery Communications, AFI opened the third annual Silverdocs documentary festival, which lasts until Sunday.

The Silver Theater is a Montgomery County facility. This year, the county is providing about $600,000 in operating support, about 15 percent of the theater's budget. The county's support has shrunk from $700,000 two years ago, said Ray Barry, the theater's deputy director.

The theater expects to exceed its revenue projections by about 30 percent this fiscal year, Barry added. A decision last year to start showing extended first-run films -- the theater will continue to screen "Crash" during the festival -- has resulted in higher revenues.

No fewer than four justices of the Supreme Court have been seen at the Silver Theater, giving Horwitz and Barry confidence that it will find a place in Washington's cultural firmament.

Barry's moment of certainty about the eventual success of the theater came in 2003, when downtown Silver Spring was all but deserted in the evenings. Barry stood outside during the opening night of a Latin American film festival and watched the hubbub as a half-dozen ambassadors arrived. "I suddenly felt like this could really work," he said.