''The Woman in Black,'' a surprise hit of the 1989 Londo season, is being given an excellent production at the Olney Theater. The direction, by Bill Graham Jr., is without flaw. The set, by James Kronzer, is completely suitable to the material, and the acting, by Leland Orser and Tony Rizzoli, is the best.
The only trouble with all this is that there is almost no play. ''The Woman in Black'' is subtitled ''A Ghost Story,'' and that, more or less, is what it is. Its weakness is that it is much ado about next to nothing. The ending is interesting. It may even be novel, but it is very little payoff.
Actually, the show isn't all that long. It just seems long. Adapted by Stephen Mallatratt from the novel by Susan Hill, the two-character drama takes place in a theater where one man, a lawyer, has asked an actor to help him stage an event that changed his life. He wants the actor to do all this in front of the lawyer's family, so that they will know why the man's life has been ''ruined.''
It was the lawyer's first case that ruined him. He has been summoned to a mansion, far removed, one that was apparently inhabited by the ghost of a woman whose child had been drowned. Ever since that tragedy, the ''ghost'' had been trying to even the score with others, their lack of guilt having no bearing on the matter.
The actor and the lawyer play a number of roles, and this may be one of the play's basic weaknesses. It is difficult to distinguish one character from the other, and in the end, all roll together.
The material itself is weak. There is a ghost who prowls her former home. The lawyer is terrified when he meets her. Fine, but it takes far too long to meet her. The first act, one hour long, is almost static. The premise is established, then nothing is done with it. The second act has more interest but not enough to save the evening.
''The Woman in Black'' opened in London last year and is still running there. The mystery in the play is far less mysterious than the success of the play.
Orser is occasionally shrill as the actor, but most of this is excusable. Rizzoli, who did so well in ''Rough Crossing,'' the previous production at the Olney, offers added proof of his versatility. Would that the play had served Orser and him better than it does.
''The Woman in Black,'' which did frighten some members of the audience at the opening performance, will continue to play at the Olney through Oct. 21. The Olney people have done their best with it, but it is just not enough.
''The Woman in Black''
** A lawyer asks an actor to dramatize a harrowing incident in his life.
CAST: Leland Orser, Tony Rizzoli
DIRECTOR: Bill Graham Jr.
RUNNING TIME: Two hours