The movie is often as dreamy as ragtime music itself, but its central figure -- a doomed black piano player named Coalhouse Walker Jr. -- is the antithesis of that. He is bright, ambitious and open-faced, with a sense of pride as unambiguous as the part that perfectly bisects his hair.

The role of Coalhouse Walker in Milos Forman's "Ragtime" is the best role for a black actor in this movie season, and probably in many seasons. More than 200 actors were considered for the part, but it went to Howard E. Rollins, 30, who stands before us now in his hotel room, glass of champagne in hand.

He's from North Avenue in Baltimore, studied at Towson State College, and played Andrew Young in the CBS mini-series "King" and George Haley in "Roots II." In other words, you've never heard of him.

"The screen test was May 11 and 12, 1980," Rollins said. "Monday the 11th O.J. Simpson was there, and Dorian Harewood, and also a guy from 'White Shadow' whose name I forget. We all knew it was going to be a great role for a black actor, and there aren't that many. One guy actually flew himself to New York to apply, and then to London, too, at his own expense. But he didn't get a part."

To Rollins, Coalhouse Walker seemed almost too much to hope for. "I thought, gee, here's a character whose dilemma could be shared by any sensitive human being -- a woman, a black or a white, a Mexican or a Chinese. He's an honest person, and he's treated unfairly. He tries to get help the usual way, but when that fails he takes things into his own hands. He has no other recourse."

Five weeks after his audition, Rollins walked into his agent's office. A secretary looked up and grinned. "Hi, Coalhouse," she said.

There were scores of characters in E.L. Doctorow's book, but Michael Weller's movie script pared them down -- dropping entirely an arctic voyage by the father. During shooting, the story was compressed still further. The role of Harry Houdini was radically trimmed. Weller had preserved the presence of the socialist Emma Goldman in his script, and much of it was shot with Mary Clare Costello in the part. But in the end the character of Emma Goldman was excised.

The streamlining left Coalhouse Walker much in command of "Ragtime" -- but what about Howard E. Rollins, talented newcomer?

"Milos was absolutely fantastic with me," he said. "A lot of times I was in awe of what was happening. I sure learned a lot about technique, fast. For one thing, Milos freaks out if he sees you're acting. One of the first things he said to me was, 'Look, you're right for the part, but just don't enjoy the acting so much.' "

Rollins does Forman's Czech accent with the growly familiarity of a son imitating a father.

"I remember once two actors were doing their lines and Milos was watching carefully. One guy was talking and the other was listening, and suddenly Milos says to him, 'No! no! no! That's not it. He's talking, but you -- already I see your lips moving, your eyebrows going up, you're turning your head just a little, you're getting ready to say something. Why? Ha! Because you know what's coming, huh? Because you read the script, huh?'

"With Milos," Rollins said, "you always listen to the other person like you're hearing him for the first time. Listening is a big deal with Milos."

The hand of the director is much in evidence in "Ragtime," and one bit of evidence is the curious tone that affects exchanges between members of the Doctorow family in New Rochelle. Mary Steenburgen, as Mother, speaks almost as in a dream; and James Olson and Brad Dourif also seem eerily distant. The effect is of a cast of actors floating on a waterbed.

Question: Was this intentional? Did Forman say: "Now, in this scene around the dining room table, I'm looking for a certain stylization . . ."?

Rollins scratches his head, sips his champagne. "No, he never said anything like that. But I know what you mean about the tone. My theory is that it came from the auditions. You read cold the first time, with Milos smoking his cigar, and watching to make sure you're listening to the other actor, really hearing him. I think the actors just really got into that, and it carried over. It was just something that happened. There was never any discussion of that."

Despite the champagne, which may be taken as a sign that Paramount Pictures figures it has a new star on its hands, Rollins felt very much the newcomer on the "Ragtime" set.

He had already been impressed by his one day of shooting with Marlon Brando, for "Roots II," in which the great eccentric played the American Nazi George Lincoln Rockwell. But Rollins had missed meeting him.

"He was on the set the day before I was, but I knew he'd been there because there were cue cards tacked up all over the place. It was like a hurricane had come through and blown them all over the trees."

Rollins declined to speculate about the use of cue cards by immortal contemporary actors, or to surmise that when you are that much in demand, memorizing your part becomes an unnecessary burden.

On the "Ragtime" set, however, he had plenty of talented company. One was the veteran character actor Kenneth McMillan, who plays a redneck fireman whose practical joke against Coalhouse Walker has national repercussions. McMillan had also played Bull Conner in "King," and was now again the very model of a salivating racist bully.

Rollins laughed. "Oh, Kenny is really something," he said. "He doesn't spare you, you know. He's really good at finding mannerisms and using them. Sure, people have asked me if there was tension between us. Naw. We partied. Kenny is Kenny."

Rollins seems a man to take things seriously, so he got some advice from James Cagney, too. Cagney came out of retirement to play Rheinlander Waldo, the New York police commissioner who is stuck dealing with a Coalhouse Walker at the end of his rope.

"Just meeting Mr. Cagney was a big thrill. You know, when he came on the set there was always someone there to escort him, someone he could rest his arm on. Occasionally the honor fell to me. The man is just awesome.

"Well, I had this death scene coming up, and I was particularly anxious about it. I went to him and said, 'Mr. Cagney, I've never died before, and I'm not sure I know how to do it.'

" 'Just die, kid. Just die,' he said.

"Actually," Rollins went on, "that fit in pretty much with Milos Forman's general theory, which was always: 'Simplify, simplify.' Another thing that Mr. Cagney told me was this: 'The most important thing about acting is this. You walk into a room, plant yourself, look the other guy in the face and tell the truth.' "

So Rollins did all those things. But what came out in the finished film is nothing like James Cagney or Marlon Brando or Kenneth McMillan. It is Howard E. Rollins, and it is quite likely that the days when most people never heard of him are over.

He still remembers the day he left Baltimore for good to make a name for himself in New York City.

"It was July 1, 1974," he said. "My father was a steelworker and my mother a domestic, and neither of them thought acting was such a good idea. It was an emotional day. My family was not happy, and there were many words of caution. After two years my father was still worrying -- he called me to say he'd found a job for me in Baltimore. It was as a cashier in a Two Guys store."

Now Rollins lives on the West Side of Manhattan, and people call him "Coalhouse," and he is drinking champagne on the road.