YOU DO IT every time you tangle with the hypnotic panoply of what's playing at the movies and decide that one specific film is most deserving of attention.

You do it whenever you ruminate on owning a theater and playing nothing but favorite films, the ones everyone would like if only they had you immaculate taste. Huey Long didn't manage to make every man a king, but certainly every man is his own film programmer.

Now imagine doing that for a living, earning ready money by picking films other people will see, having the whole history of cinema to choose from but not having to agonize too much over empty seats. "I don't think anybody thought it was a proper job for an adult," says former programmer Stephen F. Zito, "not even my mother."

Full-time professional programmers are as rare as windy speeches by Gary Cooper, for while many places - Rochester's Eastman House and the Los Angeles County Museum of Art are examples - show sporadic film series, only three major day-in and day-out film archives exist in America: the Museum of Modern Art Film Library in New York, the Pacific Film Archive in Berkeley and the American Film Institute right here in the nation's capital.

The programmers for these theaters have, as you might expect, plenty in common. They are almost exclusively male, in their early '30s, and were first fascinated by film no later than college. They've all seen enormous numbers of films in their short lives - the AFI's Michael Clark, no quite 30, estimates his total at 3,500 - and they tend to be apologetic if the exigencies of fate have kept their current viewing as low as 300 titles per year.

And they all tend to worry, brooding about things like trusting their personal taste too much and, yes, even about money: At the AFI, for instance, $240,000 of the fiscal 1977 budget of $340,000 is supposed to come from box office revenues. "I take it very much to heart when a series fails," says Clark. "If the people are not there and you can't do anything about it because the films are already booked, you know you'll die a million deaths in the next five or six weeks."

Other problems exist as well, because films are not like library books, easily cataloged and accessible, and programming them is not at all like sitting in front of a huge cornucopia, picking here, picking there.

"You can't just say, 'I'd like to show this film,'" explains programmer Tom Luddy. "You have to find out who has the rights, are there prints in distribution, if the person who has the rights is same as far as business dealings are concerned, are the prints in good condition, how expensive is it to ship from where they are. Each area can get you involved in endless, enervating conversations; I have whole fat files on films you just can't get."

Quainter problems crop up, too, like misremembering, characterized by [WORD ILLEGIBLE] formerly program planner at the AFI, as "seeing something on TV at 3 in the morning that looked real good and then seeing it again in front of people and finding out it's just incredible garbage." When that happens, Michael Clark says, "You can hear this lynch mob yelling, 'There he is.' You can't get out of the theater fast enough."

Dealing with manic archive audiences can also be a chore. As the AFI's Michael Webb delicately puts it, "Public taste is not standard, and sometimes you are dealing with people who are obsessive and possessive about film, who can't comprehend anyone who doesn't share their enthusiasm about Allan Dwan being the greatest American director ever."

And yet, despite these similarities, despite choosing from the same body of film as they all do, the three American archives and the people who decide what they show have radically different programming philosophies, philosophies that reflect differences in film theory that have been argued about since film archives first came into existence. In the Beginning

That would be 1934, when at pretty much the same time - though genteel disputes over priority still go on - Henri Langlois founded the Cinematheque Francaise in Paris, Ernest Lindgren began what became the British Film Institute in London, and iris Barry opened the Museum of Modern Art Film Department in New York.

The biggest philosophical differences were between Langlois and MOMA's Iris Barry. Langlois, a large man with a huge appetite for film, a man who stored cans in his bathtub when all else failed and whose assistant would reply to queries about missing reels by saying, "Darling, when you go to the Louvre, you don't complain because the Venus de Milo has no arms," could never understand Barry's elegantly selective view of things.

"He disapproved strongly," writes critic Richard Roud, "of her decision many years ago tht as there were only four 'great' films of Buster Keaton, those four were all she took, although the museum had been offered them all. He just didn't understand how she, or anyone could be sure."

A bit of that feeling lingers on at the museum, which sees itself as very much the grande dame of American archives. "We have a reputation that goes back beyond any others in terms of time," says Larry Kardish, assistant curator in charge of programming. "Generations have come here to the museum."

What this means concretely is that "the shows we do are very broad, very ecumenical." MOMA's about-to-begin, tribute to Universal Pictures will be an eight-month affair showing upwards of 300 films, and when the museum puts on a tribute to the little-known cinema of Senegal, it doesn't try to sneak in half a dozen examples, it grabs for all the gusto and puts 78 on the screen, like it or not. An archive of record all the way.

This mania for inclusiveness, this reputation for solidity, does have its advantages. Feeling that its Bicentennial series on comedy would not be complete without Chaplin's "Woman of Paris," unseen publicly for decades, the museum wrote to the great man and he agreed to a showing. "That indicated confidence, enthusiasm for the work the museum has been doing," says Kardish, who couldn't help but add, "Of course, it turned out not to be a comedy," but that's another story. Way Out West

At the other end of the spectrum, both physically and spiritually, is Berkeley's Pacific Film Archive, modeled loosely on the Cinematheque and probably the most spirited and inventive film facility in the country.

Much of the spirit and inventiveness comes from Tom Luddy, the PFA's program director, who says he is liable to do "everything from booking the film to typing the program notes. The AFI and the museum, they're more institutional. Here we do a lot on a little and something personal can rub off."

One way the PFA is different is that is shows sizeable amounts of politically oriented, leftist films. "Being in Berkeley," Luddy says, "we're not afraid to take certain political stances. We don't have to pretend we're objectively letting this pass through." An example was the recent premiere of the three-hour "Battle of Chile," filmed during Allende's last year in power and edited in Cuba. "The filmmakers came from Paris, two thousand people saw it at two showings, it was a rally as much as a film showing," Luddy says, still not quite believing it. "It was really something."

Having filmmakers make personal appearances is another PFA characteristic, with close to 150 showing up in a year, everyone from director Roberto Rosellini, who accompanied the most extensive American showing of his films ever, to Yoshikata Yoda, longtime screenwriter for the extraordinary Japanese director Mizoguchi.

Luddy also believes in "being sort of a beacon, in putting yourself on the line," by pushing films he feels are worthwhile even if the audience is a little reluctant, as they were for the films of German director Werner Herzog, who first drew not at all and now regularly sells out.

Yet the PFA blances this type of stuff with showings of acknowledged classics and a willingness to dig up and look at almost anything. Probably no other place in the country would mount a tribute to Arthur Ripley, a cult director's cult director whose best-known film is Rovert Mitchum's "Thunder Road." Nor would anyone else show the TV series "The Prisoner" in its entirety, something that gave even Luddy pause.

"We respected the fact that it was unusual for a TV show, that a lot of people were really excited by it, so we managed to track it down and it turned out to be very, very lively stuff," he says. "It sold out when we showed it, the people who came regularly formed a kind of club, they made buttons, maybe people even got married as a result of it." Nothing Catclysmic

Nothing this catacylsmic ever happens at the American Film Institute, where Michael Webb, who has moved up to director of national film programming after being the AFI's film programming manager since the theater began in 1969, consciously tries to steer a middle course between the East and West Coast extremes:

"The museum's series are very, very, extensive, going into byways, deadends, even going off where there are no roads at all, things that wouldn't work as a theatrical program, while Tom Luddy has the advantage of being on the most politicized, intellectualized campus in the United States. I try not to overload in any one direction, reaching too high and falling short. We run a tidy ship."

Webb's particular bailiwick at the AFI was foreign films, exposing American audiences to series that were sometimes jokingly categorized as "New From Neptune" or "Atlantis: Lost Films From a Lost Continent."

While nonbelievers scoffed and said he was "forever showing incomprehensible Turkish films about cows," Webb found that programming these films involved it own series of peculiar problems.

Some countries, for instance, think that all you want to see is bad copies of domestic efforts: "While I was in Egypt I was shown a whole slew of films by a perfectly terrible director that were nothing but an ostentations display of status symbols like portable TVs, white sports cars and apartments furnished in contrasting shades of magenta and lime green. I was told, "Surely these films should be interesting, they're so American."

In other countries - no names, please - a film will be selected an approved and then "mysteriously disappear." "I'd say, 'I know the director, I'll get his print,' and the government says, 'Oh, he's moved to another town and we don't know how to reach him." And then there are things like Claude Jutra's "Wow," which, seen without titles, "looked to be a striking, zippy film." However, once subtitled it turned out to be "atrocious, the worst kind of third-hand slang you can imagine." What, Me Worry?

Michael Clark doesn't have to worry about things like this. As the AFI's program planner, he deals almost exclusively with American films, and he deals with them in such a singular way that he admits to being "sort of the Gyro Gearloose of programming."

It all started with what he calls "this trash Ohio upbringing I had. I couldn't keep my mind off films, teachers were always coming to my parents and saying, 'We see him staring out the window thinking about some double bill.'" Some good came out of this - Clark won $16,000 on the "$64,000 Question" at the age of 10 - as well as one-of-a-kind experiences like working with Flippo the Clown, the afternoon movie host in Columbus, Ohio.

A more lasting result was what Clark describes as "my eclectic tastes, so eclectic that people say maybe I should be seeing a psychiatrist." Who else but Clark would put "I Married a Communist" and the Eddie Fisher-Debbie Reynolds "Bundle of Joy" on the same double bill, or run back-to-back showings of Carl Dryer's severe "Ordet" and Liz Taylor's frothy "A Date With Judy."

"Basically, I try to bring a sense of humor to it," Clark explains in a bit of an understatement. "I resent the 'official history of film,' the idea tht there are only a few hundred established classics. What I'm trying to say is 'Hey, a lot of different kinds of films are being made, let's take a look. It isn't as pat as the textbooks make out.' I want people to broaden their film horizons, to look at things they might not ordinarily look at, but have a good time doing it. Not all reasons for seeing films are esthetic."

There turns out to be quite an irony here, however, for someone whose conscious aim at the AFI is to recreate the good-time past of movie going, Clark finds that personally film is "not quite the fun it used to be," and in fact this turns out to be the unseen occupational hazard of the programming business.

"As I see more and more films, there are fewer and fewer I still get a charge out of," says Michael Webb, while out in Berkeley, Tom Luddy hesitates for a fraction before saying, "Yes, I still see films for fun. But I much prefer going to hear some jazz. That's real fun."

So far in 1977 Kenneth Turan has seen, give or take a few, the following films: "Madigan," "F for Fake," "Crossfire," "Laura," "Dial M for Murder," "Rocky," "The Dark Corner," "French Provincal," "Sweet Punkin," "The Pink Panther Strikes Again," "Fun With Dick and Jane," "Fellini's Casanova," "Twilight's Last Gleaming," "Kiss Me Deadly," "I Wake Up Screaming," "The Star of Midnight," "The Gracie Allen Murder Mystery," "The Kennel Murder Mystery," "Pumping Iron," "Children of Paradise," "Stagecoach," "Lancelot du Lac," "The Late Show," "The White Sheik," "Jonah Who Will Be 25 in the Year 2000," "The Rules of the Game," "Verdi," "Slapshot," "The Late Show" (again), "Welcome to L.A.," "Black Sunday," "All About Eve," "Edvard Munch," "Tarnished Angels," "Whatever Happened to Baby Jane," "Nasty Habits," "Demon Seed," "All That Heaven Allows," "Between the Lines," "Cross of Iron," "The Domino Principle," "Calamity Jane," "Ali or Fear Eats the Soul," "The Wonderful Crook," "Harlan County," "Billy Jack Goes to Washington," "Red Garters," "The Devil and Miss Jones," "Man on the Roof," "Three Women," "Damsels in Distess," "The Bachelor and the Bobysoxer," "My Favorite Wife," "Kitty Foyle," "The Outlaw Josey Wales," "The Sargossa Manuscript," "Star Wars" and "I Married A Communist."