Christopher Reeve says stardom doesn't always mean fine acting

''What effect do you want to produce? Do you want to be a star, or to act?'' That's not an idle question for Christopher Reeve. It's a decision he makes each time he prepares a new project like ''The Bostonians,'' his current movie.

Those two activities - acting and starring - are somewhat contradictory, Reeve feels. ''The true star will be careful to preserve his image through the part,'' he said during a recent interview. ''The audience feels secure, and the performer is trusted.

''But I'm much more reckless, for better or worse,'' he continued. ''I try to let the part stand on its own, without interference. We have a tendency in this country to reduce, to make things easily packaged. People are much more intricate than that, though. Parts are larger than ourselves. I like to leave the contradictions intact, not flatten them out.''

The liking for ''contradictions'' was one thing that attracted Reeve to ''The Bostonians,'' based on Henry James's 1876 novel. He plays a young Southern lawyer who romances a budding feminist named Verena, wooing her away from her mentor and her cause. ''The film has literally translated James's novel to the screen without compromising for the modern sensibility,'' Reeve says, complimenting director James Ivory, writer Ruth Prawer Jhabvala, and producer Ismail Merchant.

''One of the keys to my work in it,'' he continues, ''was not to impose my modern liberality on the character I play, who is a product of his time.'' There was no need to update the novel for dramatic purposes, he feels, given the freshness of ''the moral ambiguities of the characters and the contradictions between their aspirations and personal conflicts.''

Also fresh, he says, is the ''historical perspective on feminism.'' Although many of James's ideas were less enlightened than one might wish today, the film ''shows what happened 100 years ago .... Verena's father is a mystic, a spiritualist, a crackpot. You can see that the roots of the movement came from the seance rather than the political battlefield.''

Actual feminism, Reeve continues - ''real, practical feminism'' as he puts it - starts in the last reel of the movie, when the personal drama is resolved and Verena's feminist mentor (though smarting from Verena's desertion) proclaims that women ''will not retreat a single inch, we will be heard!''

That's when feminism is born, Reeve says. ''Up until then it's really been parlor talk.''

Reeve also feels it's a mistake to see the story as a tragedy, with an earnest activist lured away from the progressive path to serve a backward-looking husband. ''It isn't a defeat for Verena to go off with Basil,'' the actor says. ''Before that point, the whole story has been an illusion, and the characters have been in an illusory kind of place. Women standing off to one side, shrieking and ranting against men, will bring no forward movement of any kind. When a man and woman go off together to face reality, the real world is being approached. Sometimes they'll cry, sometimes they'll laugh. They'll love and care. It's not going to be easy, but it's going to be real!''

Indeed, says Reeve, ''the whole point of the story is reconciliation. The theme is unity, integration. A man from the South - he's been defeated, his whole life has been turned upside down - comes to the land of his enemy and tries to make good. The film and book are about James's view that we must put the fragmented pieces back together - North and South, man and woman, black and white, land and industry, rich and poor, for the country and for the people. Happiness depends on this. It's not going to come from women standing off in the corner.''

Talking with Reeve about ''The Bostonians,'' it becomes clear he likes the gentle, rather reactionary Civil War veteran he plays. ''It's very satisfying when you line up with a part, when you and the part meet,'' he says. ''With his romantic longings, compassion, and sense of humor, Basil is closer to myself than a lot of other things I've done.''

But liking your character is just a bonus in the acting profession - it's not a condition for success. ''You don't have to like a character to play him, as long as you don't judge him,'' Reeve says. ''Not passing value judgments is what you're trained to do. Otherwise how could you play anyone? It would all be reduced to you. It's the actor's job to be truthful to a part but never reduce it just to oneself. You have to rise, to be generous.''

This seems to touch the heart of Reeve's philosophy. ''When an actor is hired for a part,'' the performer says, ''he brings his own authority and knowledge. Depending on his motives, he will challenge himself to whatever level he thinks he can deal with. I hate to name names, but take (Robert) Redford and (Paul) Newman as examples. I think each has decided, over the years, how much he wants to be an actor and how much a star. Someone once said there's a difference between Newman when he acts and when he's being a star. You can sometimes tell whether he's really working, as he was in 'The Verdict,' and when he's not.

''I'm still young and green enough that I get up there and really try to play the part every time - with varying degrees of success, because I take enormous risks.''

Reeve admits he didn't always have such a firm perspective on his career. ''Right after 'Superman' I took myself much too seriously,'' he recalls. ''I demanded, in a fairly aggressive and pompous way, to be accepted for a range and talent I knew I had.

''But they don't have to do that, of course. They can take me for Bozo the Clown if they want. So after a couple of years I got off that kick and quietly went about my business. And now I'm happier, the audience is happier, the parts that come my way are better. The less I worry about my versatility, the more it just happens.''

Reeve feels he belongs to a group of young actors who manage to ''have their cake and eat it, too'' - by combining stardom with real acting. The group includes ''people who were around the Juilliard School around 1970 to 1974,'' including such performers as Kevin Kline, Mandy Patinkin, and Robin Williams. ''They trained seriously and probably weren't aiming for stardom,'' Reeve says. ''If it happened, fine, but to 'make it' - to fly first class, get recognized on the street - wasn't seen as the desirable achievement it once was.

''Today's star doesn't encourage the audience to believe there's a resemblance between his screen persona and the real person. And this is why you'll find Kevin Kline working for free in Central Park, or William Hurt in an Off Broadway show. ... It's because self-expression comes first. If you can do that and also make money and be seen in the movies, fine. But being a headliner isn't the big banana it used to be.