Andy Warhol was more of an alchemist than a painter. He would take source material, like an image of Marilyn Monroe, and, using silkscreen printing, transform it into something different. But a lawsuit is asking whether Warhol—and many other contemporary artists—violated the copyright of the photographers whose work they used as source material, or whether their alterations led to fair use.

The Associated Press reports that the current case stems from a 1981 photo shoot that well-known celebrity portrait photographer Lynn Goldsmith did with the pop artist Prince for Newsweek. The images ultimately did not run, but in 1984 Vanity Fair licensed one of the black-and-white photos from Goldsmith for $400. Andy Warhol was given the image to create an illustration for an article the magazine was putting together on the Purple One.

Warhol did his thing, creating 16 artworks based on the photo, which became known as the Prince Series. One of them, a purple image of the pop star, ran alongside the article. Goldsmith, however, did not see the work at the time. Only after Vanity Fair republished the article online along with the Warhol illustration after Prince’s death in 2016, did Goldsmith see it for the first time.

At the time she claimed that the work infringed on her copyright. But she didn’t fire the first legal shot. Instead, in April 2017, the Warhol Foundation for the Visual Arts, which licenses Warhol’s work, sued Goldsmith, claiming she was trying to “shakedown” the organization. It called for a “declaratory judgment” that the Prince series did not infringe on Goldsmith’s copyright and that the works were transformative and subject to fair use. Goldsmith countersued and the parties asked the judge in the case to issue a summary judgement, meaning the case would not go to trial.

On Monday, U.S. District Judge John G. Koeltl ruled in support of the Warhol Foundation.

“The Prince Series works can reasonably be perceived to have transformed Prince from a vulnerable, uncomfortable person to an iconic, larger-than-life figure,” he said. “The humanity Prince embodies in Goldsmith’s photograph is gone. Moreover, each Prince series work is immediately recognizable as a ‘Warhol’ rather than as a photograph of Prince — in the same way that Warhol’s famous representations of Marilyn Monroe and Mao are recognizable as ‘Warhols,’ not as realistic photographs of those persons.”

The Warhol Foundation, of course, is happy with the ruling since it protects the Prince Series and sets a precedent for similar work by Warhol. “Warhol is one of the most important artists of the 20th century, and we’re pleased that the court recognized his invaluable contribution to the arts and upheld these works,” foundation lawyer Luke Nikas tells Sarah Cascone at Artnet news.

Goldsmith says she will appeal the ruling and that the legal battle isn’t about money. In fact, so far Goldsmith has spent $400,000 on the case and expects it will cost $2.5 million before it's done. If she loses her appeal, she may also have to pay the Warhol Foundation’s expenses. “I know that some people think that I started this, and I’m trying to make money,” she tells Cascone. “That’s ridiculous—the Warhol Foundation sued me first for my own copyrighted photograph.”

“My hope is that more of the visual community, particularly photographers, stand up along with me to say that your work cannot just be taken from you without your permission, and to show their support of the importance of what the copyright law can mean not only for me, but for future generations,” she says.

This is by no means the first case where photographers and visual artists have butted heads. In 2015, artist Richard Prince was sued for his 2014 work “New Portraits” in which he displayed screenshots of Instagram posts by other people with some of his comments added.

Other well-known artists--including Warhol--have previously been sued for violating copyrights. Jessica Meiselman at Artsy reports photographer Morton Beebe sued Robert Rauschenberg for including two of his photographs in the 1974 print “Pull.” Rauschenberg ultimately settled in 1980, and Beebe received $3,000, one of the collages and a promise to be credited in the work.

In 1964, Warhol was also sued by photographer Patricia Caulfield, who recognized her photo of hibiscus flowers as the source material for the Warhol series “Flowers.” Caulfield won that case, too, and was awarded $6,000, two prints of the artwork and royalties on future sales.

The Copyright Act of 1976, which came into effect in 1978, however, changed things for artists. It asserted that transformation of the underlying work was considered “fair use,” the standard that is now in force today.

Berry Werbin, Goldsmith’s lawyer, tells the AP it’s that looser definition of fair use that he hopes to challenge. “Obviously we and our client are disappointed with the fair use finding, which continues the gradual erosion of photographers’ rights in favor of famous artists who affix their names to what would otherwise be a derivative work of the photographer and claim fair use by making cosmetic changes,” he says. “[I hope we] will be successful and pull in the reigns of transformative use where photography is concerned.”