Seattle -- FOUR MONTHS after a play based on the life of singer Janis Joplin was closed because of a lawsuit by the Joplin estate, a federal judge here has ruled that the production is a protected form of free speech.

The ruling, by Judge John C. Coughenour of U.S. District Court in Seattle, is one of the few nationwide in which a court has tried to define the commercial rights of a celebrity's estate.

Joplin, the Texas-born blues and rock artist, died of a heroin overdose in Hollywood in 1970 at 27.

Joplin's family, joined by Manny Fox, a New York producer who owns the rights to make a film and play based on her life, asserted that the Seattle theater company could not stage the play "Janis" without permission of the estate. In the suit, the estate claimed "the exclusive right to exploit stage productions, theatrical films and television productions based on the life and times of Janis Joplin."

The central legal issue is the "right of publicity," which grants an estate control over a dead celebrity's name and style. Only a handful of states have enacted such laws, and they are usually limited to T-shirts and souvenirs, not artistic expression.

In this case, the judge cited California's law, which exempts plays, books or musical compositions from the right of publicity. That law, Coughenour wrote, applies only to merchandise, advertising and endorsements. When the celebrity's name is used in a play, it is a protected form of free speech, he wrote.

The decision leaves open the question of copyright infringement for two songs that were used in the play. The estate says the producers did not have full permission to use the songs.

The case touched on issues likely to affect anyone seeking to capitalize on the life and career of a dead celebrity, from the legions of Elvis Presley imitators to impersonations by comedians.