"Eight Minutes to Midnight," the documentary portrait of pediatrician, author and nuclear activist Dr. Helen Caldicott (it opens a 10-day run at the Biograph on Tuesday), represents a minor triumph for independent film production. Most independent films are subsidized by grant money, but more than half of "Midnight's" $200,000 budget was raised by really small contributions from individuals and organizations--$100 here, $50 there, $200, $5; the methods ranged from bake sales and over-the-transom contributions to a Boston-to-Cape-Cod "bikeathon."

The unusual grass-roots campaign was necessary, according to producer-director Mary Benjamin, who started work on the film in February of 1978 after seven years at the PBS station in Boston. "I'd never raised a cent, never made an independent film, or a film of this length," she said. "I'd made 50 short films about kids including "Zoom," for which she won an Emmy in 1977 ." Benjamin's initial impression of the founder of Physicians for Social Responsibility came from a magazine photo; Caldicott's concern and commitment shone through and drew Benjamin into the article, though her initial reactions about the nuclear issue had been, "It's too depressing, too boring, I can't understand it."

"The fund-raising process was tremendously politicizing because it was so hard," Benjamin says. She used her own savings for initial shooting in May of 1978 and started knocking on foundation doors. Her father made the first major contribution--$500. Four months later, Benjamin received two grants totaling $8,000.

Finally, having exhausted the limited sources of independent film funding, Benjamin held her first benefit screening in her Boston lawyers' apartment, with a 20-minute reel of early rushes. It was a beginning. The National Endowment for the Arts also contributed $15,000. Had "Eight Minutes to Midnight" won the Academy Award for which it was nominated last year, Benjamin might still be reciting her thank-yous.