By Matthew Kalman

Jerusalem

More than half a century after Albert Einstein's death, companies continue to challenge Hebrew University of Jerusalem's tight grasp on the physicist's likeness.

In the latest effort, Forum Novel­ties Inc., a costume wholesaler in Melville, N.Y., filed a lawsuit last month in the U.S. District Court for the Southern District of New York against the university and its licensing agent, GreenLight LLC, asserting the company's right to sell an Einstein costume as part of its "Heroes in Disguise" line.

Retailing for $11 to $26, the costume was described by one online shopper as a good value and a "perfect fit for elementary-age mad scientists."

Einstein died in 1955 and bequeathed his intellectual property to Hebrew University, where he was a founding governor. In 2009, Einstein's image earned $10-million in royalties, down from $18-million in 2008, according to Forbes, which listed him as the eighth-highest-earning dead celebrity. Last year, the university sued General Motors over ads with a raunchy Einstein image in People magazine and denied permission for the dead scientist's picture to appear in vodka ads or at a Madonna concert. But GreenLight said it was pleased to help when Chrysler wanted to use a photo of Einstein in a television commercial "to imbue the rugged but intelligently designed Ram truck with human attributes like 'brain' and 'brawn.' "

According to its court filing, Forum argues that the university "cannot 'inherit' rights from Albert Einstein that did not exist at the time of his death." The company maintains that Einstein's bequest could not have included his image because in New Jersey, where he died at age 76, he would have had a right of publicity only if he had exploited his name commercially before he died. Forum also claims a First Amendment defense, saying the costume is "intended to be worn by children acting in historically based school plays and in every day play."

Lloyd J. Jassin, an intellectual-property lawyer in Manhattan, observed on his firm's blog, Copylaw: "Forum is hoping that the court will see its Einstein disguise kit not just as a commercial product, but as an expressive or communicative work, like a biographic book or film conveying some historical fact."

"The case ultimately turns on New Jersey law," Mr. Jassin wrote. "New Jersey was the place where Einstein last lived. As such, that state's law governs the post-mortem right-of-publicity issue."

The university said that while it was confident it would prevail in court, it was disappointed that Forum Novelties had rejected negotiations and pursued legal action.