HE WARMS up to people kind of slowly," actress Nancy Allen warned before she introduced her husband, Brian DePalma, on the set of "Blow Out" in downtown Philadelphia. And in fact, our first encounter consisted of a handshake, a mumble and a long follow shot of DePalma's rumpled fatigue jacket moving across Market Street toward a crowd of extras.

But there had been a palpable warmth behind the close-lipped smile, and the man was, after all, in the midst of spending $750,000 that June weekend to reshoot two minutes' worth of film that had been stolen from a parked truck.

DePalma, 40, son of Philadelphia orthopedist, was directing the movie he hoped would bring him into the elite group of "movie brats" -- people like Francis Coppola, Martin Scorcese, Stephen Spielberg and George Lucas -- who had beaten hollywood at its own game. Filmways, in the person of its president George Litto (he was once DePalma's agent) had given him an $18-million package that included John Travolta.

His tousled, thinning hair and bearlike amble gave him a casual air, but as he watched his crew lever a "crashed" jeep into a department store window, DePalma was brooding: "My movies are like a schematic diagram in so many ways. They have all sorts of interesting cinematic ideas. But it's very important to make the people work in their relationships or the audience will fall asleep."

Several weeks later, I saw DePalma for a second time, at a press luncheon in Manhattan. By now the reviews on "Blow Out" were mostly in, and while it was the subject of controversy, muck like such previous DePalma films as "Carrie" and "Dressed to Kill", viewers were not falling asleep."His biggest leap yet," said longtime supporter Pauline Kael, comparing him to Altman and Coppola, ". . . to the place where genre is transcended and what we're moved by is the artist's vision." Veronica Geng's review in the Soho News sought to take the curse off DePalma's much-argued-about use of women as victims, finding a theme of "the survival of one women through another in a triumphant sisterly chain."

Others differed. Time and Vincent Canby were slighting, and New York's David Denby said "Blow Out's" "mixture of manipulation and tragedy doesn't work . . . maybe next time." By the time DePalma got in range of my table of questioners, he was prepared to be sarcastic, even feisty, but somehow amiable; he let go of more than a couple bellylaughs.

DePalma: "Well, let's see, I haven't gotten too many sex and violence questions yet. have I come to the right table?"

Q. Doesn't the controversy wear you down?

"When you deal in those areas you polarize people. I wouldn't do 'Dressed to Kill' any differently today. It's like "The Wild Bunch' -- some people thing it's dreadful, I think iths great movie. It has to do with the taste of the audience. Some people hate those movies and they're never gonna change. These movies will always be controversial -- nobody's gonna say, "Well you did sex and violence beautifully, I loved the way you cut the head off that person.' But I don't think that should stop you from making them."

Horror movies seemed to be a trend last year. now . . .

"I think it's very dangerous to try to cater to a market, because things shift around so much.I mean, last year we had a lot of horror pictures, this year we're into fantasy and escapism. It's hard to tell exactly -- those guys in California spend endless amounts of time trying to figure out what people are gonna want to see.

"I try to evolve step by step, to do a little different thing each movie. You have to place your career over four decades. It's very strange how people peak very fast. I remember in the early '70s all we were talking about was [Billy] Friedkin and [Peter] Bogdanovich and where are these guys now? Were they never any good? Or what happened? Because Friedkin was, 'French Connection' was a fabulous movie."

"Blow Out" is quite a contrast to say, "Home movies," which you made recently with students helping.

"I tried to take a little step, and ended up doing a movie which a lot of people did not like and nobody saw. I did it at such a small level that it was not like your 'catastrophe' picture, after which everybody says, 'You're washed up, you'll never get a job again.' But I was trying to show how to make a kind of low-budget, very personal comedy, and people treated it like anything else coming down the pike. They said, 'This is a terrible, awful movie and why are you boring us with this garbage?'"

At a certain level you become a target.

"You have to be really big to become a huge target. Like Woody Allen -- they really came after 'Stardust Memories.' That's at the level where you get 'masterwork' reviews. I've always sort of been at the middle level. They say, [laughing] 'Well, it's a DePalma picture.'"

Was Travolta your first choice for the main character?

"No, I was chasing around Al Pacino and Richard Dreyfuss, when John called me about another project. I had never thought of John 'cause I didn't think he was old enough, I hadn't seen him in about five years. I realized he's grown up since 'Carrie' -- he looks like a man in this picture."

His character's reaction in the closing scene is impressive.

"That was his idea. We tried a whole bunch of different reactions. First we tried it bland, then we tried it weepy. When he was doing, like, his sixth 'weepy' take he went into 'deranged,' and I said, 'Hey, wait a minute, let's give you a cigarette with an ash this long, and play it deranged'. That was the one he liked best, and so did I."

Did you worry about the title evoking "Blow-Up"?

"I like the title because it was about the critical sound in the movie. I knew I was getting into dangerous waters because of similarities to 'Blow-Up' but I didn't care. It was a good strong title -- all the clues in the movie are basically sound clues. It's like the comparison to Hitchcock -- every time somebody steps into a bathtub it's Hitchcock-land. It's just sort of a parody with me sometimes -- I've watched all those movies just like you people, and they're fun and sometimes they're ridiculous."

There's also that aspect of political paranoia, which is reminiscent of movies like "The Conversation" or "The Parallax View."

"This movie's just full of every political kind of motif -- you know, full of the Kennedy asassination, Chappaquiddick, Gordon Liddy, Watergate -- all our tradition [laughing] and history."

Any Abscam in there?

"I didn't get into Abscam, but I will, I will. What's amazing about Abscam is -- can you imagine sitting in a room with somebody who's handling you $50,000 in a case and not thinking something was not right? The corruption is just so day-to-day; 'Yeah, we'll help you out . . .' In 'Blow Out,' one thing you learn is that people make mistakes. It's like Rockefeller's death, they had a political/sex scandal on their hands and they wanted to clam it up, but things happen. A doesn't know what B is doing, and a lot of things set swept under the carpet. But it's not a lot of people sitting up on Mount Olympus figuring everything out."

What's your next project?

"I'm starting work on a script that Scott Spencer's going to write about the Yablonski murders, based on a book called 'Act of Vengeance.' What intrigues me is this kind of family of murderers responsible for the killings, and how they came into conflict with the Yablonski family. What's incredible is the stupidity and haphazardness of the murders -- the license plate of the car had already been written down before they walked into the house. And Tony Boyle set up the whole way it was done." [DePalma has just signed with United Artists to write and direct an action adventure story to be set in Chicago and Latin America, and rumored to be based on the 1947 film, "The Treasure of the Sierre Madre."]

Again that aspect of almost accidental evil, like "Blow Out"?

"Yes, the fumbling. Like having Gordon Liddy on your staff. You hire the wrong people, and sometimes goes wrong. Iths not a conspiracy where all the chess pieces are moved around. It's haphazard."