Just how long is a "Star Search"? For Geraldine Brooke, the first Washingtonian to appear on the nationally syndicated program, the answer is five months. That's how much time elapsed between her sending out a demo package (tape, 8-by-10 photo and resume) and her appearing on the show this Saturday at 8 p.m. (on Channel 5, with several repeats).

Actually, the show was taped in Hollywood Nov. 8. Brooke is entered in the female-vocalist category, "the first that evening," she points out. The song is Irene Cara's "Out Here On My Own." Brooke, who does jingle work and the occasional benefit concert (including an annual affair at the National Institutes of Health), is a veteran of the local music scene, having spent the years between 1965 and 1971 in a folk duo known as Patty and Gigi before settling in to solo work.

When she sent the "Star Search" people her demo in July, Brooke recieved the polite and classic "don't call us, we'll call you" routine. Except that in this case they did call, to set up a September videotaping session at Omega Studio "as the next phase of the audition process."

The videotape passed review panels in New York and Los Angeles and in early November, Brooke was flown out to perform before a live audience at the Aquarius Theatre. She was asked to send a tape to producer Bob Banner, "with the song you want to do in exactly the format you want to do, along with lead sheets and chord charts. They basically use the same arrangement you have and orchestrate it to show you off in the best way possible."

There were rehearsals (with tape) before a camera crew "so that they know where you're going, but the first time you play live with the band is that night."

Brooke still hasn't seen the final tape, but "everyone told me I was excellent. I'll see it when 25 million people see it. I'm hoping this will be the door opening for me to get into the business."

She'd rather have done one of her soft-rock originals, Brooke says, but "you're only allowed two minutes and I wasn't in the singer-songwriter category. My writing tends to be on the conservative side, vocally, so we needed something to show my range and talent."