The scarcity of roles open to black actors prompted Joe Morton to leave the drama school at Long Island's Hofstra University.

He has had no such problem lately.Morton co-stars in ABC-TV's "Equal Justice" and recently completed starring in "City of Hope" for director John Sayles.

At the moment he is employed with Arnold Schwarzenegger in "Terminator II." His film credits include "Tap," "The Brother From Another Planet," "The Good Mother" and "Zelly and Me."

Morton is not a man content simply to find work. He seeks quality roles that advance not only his career but the cause of blacks, parts with credence and dignity that dispel stereotypes.

The son of a career soldier, well-educated and candid, Morton is an effective spokesman for black performers, although he does't present himself as such.

"For `Terminator II' I went to read for (director) James Cameron," Morton said in an interview. "The script was very different from the thought-provoking films with serious themes I had done in the past. This one is an action-adventure drama.

"I can't say much about my part in `Terminator.' The producers made us sign a statement promising not to give away the story. (But) I play a scientist. It's not the leading role, of course, but he is a central figure to the plot. He's a good guy who doesn't get involved in much of the physical stuff."

Morton was eager to star in TV's "Equal Justice" for similar reasons. He portrays a tough-minded prosecuting attorney, a black professional, in a constructive light.

"It's important to me to play men who use their brains, not just brawn," he said.

"Michael James (his character in `Equal Justice') is a passionate attorney, a firebrand, and so is the scientist in the movie. In that sense, I suppose I walked into my interview with Cameron with a quality he was looking for.

"I'm not even sure he had seen `Equal Justice.' It's possible he saw me in `The Brother From Another Planet.'

"I find my role as the scientist appealing because it is the first sci-fi film in which I've seen a black character with some resonance both to the past and the future.

"In most science-fiction pictures the black guy is either an engineer or a radio operator and he is the first guy killed - gone from the movie. As Richard Pryor once said, `Whenever someone made a sci-fi picture it looked like we aren't going to be here in the future because we're never on screen.'

"Even on TV there are very few sci-fi movies or series - except for `Star Trek' - that have a main black character. In that sense the scientist I play is important. He's not just there for symbolic reasons.

"It's a small breakthrough, which has been the cornerstone of my career, to insist there are roles that black actors should play and can play - and to get producers to see the possibilities.

"That's how I got the role in `Equal Justice.' Originally the character's name was Michael Carelli and was supposed to be played by an Italian-American.

"My audition was for a black character who was only in the pilot episode. I asked to read for Carelli and they were impressed. Later I was offered the other character. Still later they asked me to fly from my home in Brooklyn to read for Carelli. They changed Carelli's name to Mike James and gave me the part.

"To me that was important. Instead of playing pimps, thugs or drug addicts as blacks did in the 1960s and 1970s, the image is changing to thinking characters who aren't bad guys."

Morton is obsessed with altering the image of blacks on screen, determined that minorities be represented in jobs and situations in which they are involved in real life.

It is more than lip service. Morton turned down a chance at the pimp role in "Street Smart," a part that won Morgan Freeman an Oscar nomination.

"I'm glad Morgan got the nomination, but when I read the script I didn't want to audition," Morton said. "I was offended by it. It was nothing new. I'd seen it all through the 1960s and 1970s. Morgan brought something to it that was very nice, but I was looking for other images.

"I want to put something on the screen that audiences have never seen black actors do before, roles that will widen views of who African-Americans are."