STUMBLING FROM STAGE TO SCREEN . . .

Turning a camera on a stage play is easy. Making a movie out of a stage play is hard. Anyone who doubts it should see three recent stage-derived films: “Children of a Lesser God,” “Extremities” an’night, Mother.”

“Children” comes closest to having the authority it had on the stage but, at a crucial point, backs away from the responsibility. “Extremities” begins boldly but falls into confusion halfway through. “ ‘night, Mother” doesn’t work at all.

What went wrong? Something different in each case. But a general lesson can be drawn. The first step to making a play work on the screen is understanding why it worked on the stage.

Was it a piece whose effectiveness came from the fact that it was on stage? Or did its strength come from the story it had to tell--a story that the screen might be able to show more fully?

This is easy enough to judge in the case of “A Chorus Line,” which everyone in his heart knew would fall flat on the screen. Big Broadway musicals are ritual events. You can’t pack them into a can.

It’s much harder to judge a straight play that doesn’t seem particularly stylized. The story appears to be the major strength here, and a good story ought to make a good film, all things being equal.

Ah, but they never are. The smart film maker realizes that all plays are stylized. Even the most straightforward little story--” ’night, Mother,” say--relies upon cues and strategies peculiar to the stage. Unless the film maker can find their screen equivalences, the story that had seemed so inevitable in the theater may seem contrived on the screen.

It follows from this that any scene that had seemed the least bit dubious on the stage had better be rigorously re-examined by whoever is doing the screenplay. It’s interesting that all three of the movies under discussion falter on points that were problematic in the original play but that the director and playwright were able to finesse.

“Extremities” is the most glaring example. This made a gripping stage play--the 20th-Century version of the Jacobean revenge play. But it did cross your mind to wonder about the behavior of the heroine’s house mates on finding that she had been attacked by an intruder, who was even now corraled in their empty fireplace. This emergency would seem to call for clear-cut action of some sort, particularly with their friend so close to the edge that she is talking about killing the intruder.

Instead, the roommates dithered, squabbled and generally behaved the way helpless females are supposed to in a crisis. It was a condescending image, but it didn’t take away from the visceral excitement of the play.

The movie adds a second attempted rape and so should be twice as visceral. But observe what this does to the roommate problem. If the heroine’s friends know that she has already been attacked in a shopping mall, yet still leave her alone in the house for the day and still behave like idiots when they come home, our attention has got to go to them. Why are they behaving this way? Is it some kind of plot to drive the heroine, Farah Fawcett, crazy? Why is she staying with them? Doesn’t she have any real friends?

Clearly, the screenplay (credited to playwright William Mastrosimone, with “additional dialogue” by five other people) doesn’t have any answers. The camera jumps from one anxious face to another, but we don’t know who belongs to each face, and we’re about as involved as if this were a cop show. In “opening up” the story, the movie perversely underlines in crayon what was wrong with the story from the start.

Yet it’s not necessarily a sin to “open up” a play. I rather enjoyed the new scene in “ ‘night, Mother” where the married brother delivers a casserole to the mother, taking care not to come into the house. This conveyed a sense of the rest of the family that we didn’t get in the play.

The problem here was twofold. Problem one: the cast. Rather than use actors whom we didn’t know to play the mother and the suicidal daughter, director Tom Moore used stars. Stars who are good actors, too--Anne Bancroft and Sissy Spacek.

But we catch them acting, particularly Bancroft. Her stoop, her dotty-old-lady ways, are well observed, but they’re overly projected, not quite to the point of caricature but approaching it. Spacek gives a more natural performance, but she’s so clear-browed and indomitable that it is impossible to see her as a lumpish young woman who has nothing to live for.

So again a question comes up that the play had managed to keep in the background. Why would a daughter tell her mother that in exactly 90 minutes she is going to go into her bedroom and shoot herself in the head? Playwright Marsha Norman’s official answer was: So that the mother and the daughter will have a chance to say goodby.

But with Spacek so in charge of herself and of the situation, one could read the answer as: To teach mama a lesson. This isn’t a direction that the viewer’s mind should be going in if “ ‘night, Mother” is to raise a lump in his or her throat.

Problem No. 2: Norman’s play (she also wrote the screenplay) is a seesaw battle between two women. The pressure builds more inexorably when they are both in the frame (the ring, so to speak) at all times, as in the stage version. Close-ups and reaction shots are like little nicks in the flow, and director Moore doesn’t make particularly thoughtful use of them. “ ‘night, Mother” would have made a fine TV play, back in the days when they were done live. On the big screen, it’s a recording of a performance that doesn’t happen.

“Children of a Lesser God” is the biggest achievement of the three, and the biggest disappointment. Director Randa Haines puts Mark Medoff’s story on the campus of a New Brunswick boarding school, and the course of Sara and James’ romance follows the arc of the school year from cold winter to budding spring. The film is beautifully imaged--as when the swimming pool is seen as a symbol of Sara’s silent world--and it’s intelligently acted by William Hurt and Marlee Matlin.

Alas, Haines has escaped all the technical pitfalls of bringing a play to the screen only to succumb to the ethical pitfall. She doesn’t trust the movie audience to be as intelligent as the theater audience. She doesn’t want to get into Sara’s attempt to become a spokesman for the deaf. She doesn’t want to end the story on a questioning note but on a happy one. Hollywood, she has told an interviewer, is uncomfortable with ambiguity.

Granted, Sara’s adventures in politics were the cloudiest scenes in Medoff’s original play. (He shares credit with Hesper Anderson for the screenplay but was actually dismissed from the project.) But Sara’s entry into political activism was more substantial than the vague business that separates the lovers now--until spring and their equally vague reunion. “Children of a Lesser God” was originally a love story that made you think. Now it’s a love story that doesn’t want you to think. The final danger of making a play into a movie, it appears, is that it will be a Movie of the Week.