If you ask Margaret Carroll what she thinks of her son's movies, a blush creeps up her face. "I would never let his grandmother watch them," she says. "And there are certain people I wouldn't invite over when they've showing - like the priest."

Not that Pat Carroll, 23, a University of Maryland senior, takes after Russ Meyer, or yearns to project the pre-born-again fantasies of Larry Flynt on the screen. It's just that the Wheaton, Md., neighbors often wonder what kind of twisted mind could spawn characters like Dr. Spiro Keets, the mad professor. In "Cloning Around," 15 minutes of sci-fi slapstick that Carroll whipped together with three suburban buddies and $400, Keets clones an army of Shriners, unleashing the bloodthirsty mutants on rowdy students.

Carroll's brainchild, Travesty Productions, has cast neighbors, friends, brothers and sisters in a handful of low-budget creature features: "It Came From Marlow Heights," "Curse of the Atomic Greasers," "Invasion of the Paramecium Men." He finances these productions by working in a nursing home kitchen. The latest is "Insurance Salesman From Saturn."

It unreels, along with 12 noble efforts by local filmmakers of varying talent and means, Monday and Tuesday evenings (7 and 9:30 p.m.) at the Biograph's twice-annual competition. First prize is $50 and a book of 10 tickets, good for any show, except Friday, Saturday and Sunday nights. Hardly an Oscar.

But Carroll, a shy, shuffling young man with dark hair and Woody Allen aspirations, and partners Bill O'Leary, Larry Zabel and Jim Phalen, are willing to show their movies to anyone, anytime. Carroll views the "Expose Yourself" show as just one mor chance to trot out characters like Dr. Keets and "The langley Punks," a trio of suburban cutups who figure heavily as Stooge-like victims in the comicmonster movies.

"After seeing this film, you'd never guess we went to a nice Catholic high school," he says.

Last year American colleges and universities graduated about 30,000 film or broadcast majors into a job market unlikely to accommodate them. Greg Epler, editor of the WAFL book, the Washington Area Filmmaker's League directory of local freelance technicians, writers, actors, editors and directors, guesses that about 4,000 people earn - or try to earn - a living working in films in this area.Many toil in government audio-visual departments, or ad agencies, or production companies that make training films for the government. Few, syas Epler, can support themselves by turning out the independent films they want to make. So it goes for amateur Altmans.

Take Robert Clem, 31. He has entered the Biograph show with a gentle, 13-minute film (black and white) called "Chinese Laundry," about a boy and a girl who accidentally pick up each other's laundry and keep barely missing each other in an attempt to return the packages. Clem is a criminal lawyer.

Valerie Blitz ("Vogage to the Dinner Table," a six-minute experimental entry), 25, has spent two years searching for a film job. Tom Allen, 22, a Hamilton College graduate who based his dramatic short, "The Night the Bed Fell," on the James Thurber short story, hawks cameras on Pennsylvania Avenue. Peter Swanson ("When I Grow Up," six minutes on firmemen), 21, tends bar for $3 an hour at Valle's Steak House in Rockville.

"You've got to eat somehow," he says, "If you want to make independent films, you always need a backer. Unless you're a George Lukas or a Stanley Kubrick, you've got to hustle."

Among the hustlers at the Biograph is one Michael Day, 29. He is luckier - and perhaps more talented and driven - than most. Day teaches filmmaking at the Corcoran Gallery to pay the rent; and, over the last five years, he has managed, with two grants from the National Endowment for the Arts and funds from collaborator Carl Colby, to turn out a number of graceful, finely crafted films. "Fat Tuesday," shot at the New Orleans Mardi Gras, won last year's Biograph show. And this year, he was offered up a 15-minute impressionistic bit on a woman giving birth, "Blossom in Virgo."

Pat Carroll first picked up a movie camera because his mother was allergic to parakeets - his. It was heart-wrenching, parting with the bird. But the Brownie Super-8 he was given dried the tears. He was in the sixth grade. Childhood was spent in front of the TV, watching the Marx Brothers, Laurel and Hardy, the Three Stooges and sleazy sci-fi movies like "The Brain That Wouldn't Die" and "Night of the Living Dead."

The camera, eventually traded for a 16mm, wound its way to the back roads of Langley Park, where Carroll has shocked more than one motorist. One VW rounded a bend to find Professor Farfromsane in the middle of the road beating his hunchback side-kick, K-Mar, with a cane. The cops arrived shortly, and Carroll had some explaining to do.

The homemade horror shows generally take a day to shoot, depending on which friends Carroll can round up to play the especially "deranged" parts. For the slapstick sadists, he writes subtitles like, "I won't harm a scab on your face," and allows the extras to wave beer in the background. "We're beyond embarrassment," he says, "there isn't a whole lot that shocks us anymore."

For those who can afford a portfolio, competition for film grant money is vicous. Last year, the American Film Institute, the largest supporter of independent filmmaking in the country, awarded some $300,000 in funds from the National Endowment for the Arts to 43 independent filmmakers in chunks of $500 to $10,000. The AFI received more than 1,000 grant proposals, says Arts Endowment specialist Don Drucker, with the final awards going to filmmakers with a track record.

Some past recipients like director John Appleson ("Bound for Glory," "Save the Tiger," "Joe") and John Hancock ("Let's Scare Jessica to Death" and "Bang the Drum Slowly") have managed to parlay their grant-funded films into reputations and, eventually, Hollywood. But for neophyte filmmakers, grant money remains the impossible dream.

Catch-22 illustrates the economics of independent filmmaking: Even if you can lend enough money to make a short (less than 50 minutes), you will be hard-pressed to find a theater to show it. Commercial movie houses rarely, if ever, show shorts, which eat away at the hours in a day available to run a "Jaws" or a "Star Wars." That leaves the distributors that specialize in peddling shorts (good luck in getting your investment back), public television (low pay, but good exposure) or network TV (dream on).

There are about 10,000 independent films (short and non-features) cranked out in the U.S. every year, says Charles Samu, 28, vice president of New York City's Phoenix Films, a distributor concentrating on shorts. Weed out the drivel and that leaves maybe 3,000 films ranging from mediocre to brilliant. "Only a handful of those get nationwide network TV exposure," he says. "It's not the easiest way to make a buck."

A deal with a distributor works like this: Someone like Phoenix buys all rights for a period of time. A filmmaker might get the low end of a 25-75 split. For an independent to recoup at $10,000 investment, Phoenix would have to sell 100 prints (at $400 each) to schools, libraries, health departments and church groups across the country. Michael Day has Phoenix distributing "Fat Tuesday," a documentary Samu considers successful, although it hasn't made money after two years in the catalog.

Phoenix is always looking for "good children's films that don't talk down to children," and topics that may prove trendy. Films on drugs, alcoholism and minority grievances were big in the '60s. The trick is to crystal-ball the trends of the late '70s - maybe films on child abuse, wife-beating and homosexuality, Samu suggests.

It is cold and dark outside as Pat Carroll rumbles home in his battered pea-green Chevrolet four-door. He threads "It Came From Marlow Heights" through the projector, douses the living-room lights and opens a can of Budweiser. What comes from Marlow Heights, a portion of suburb Carroll finds noxious, is a friend he has cast in a $40 monster mask who goes around chopping heads with an axe and devouring the brains. "It's really tapioca, but we don't tell anybody."

The retrospective proceeds, amidst the comings and goings of family who stop to chuckle, and move along. And as the projector begins to whir with "Curse of the Atomic Greasers," and professor Farfromsane de-atomizes the Langley Punks to a rock quarry near Calverton, it is evident how much Carroll and company have learned over the years as slapstick auteurs. There is always a chance, he tells you, he could be the next Mel Brooks in the making. "Look how far we have come," he says. "A few years ago, when we ran out of ideas in a scene, we'd just start throwing food. Maybe we'll get a break. I heard Paul Newman was selling encyclopedias when he was discovered."