Five years ago this summer, art-world types were buzzing with news of a major discovery: a long-hidden cache of paintings and sketches by Jackson Pollock had been found in a rented storage locker in East Hampton, Long Island. At the time, the works’ pedigree seemed all but certain — after all, the locker had belonged to Herbert Matter, a Swiss-born artist and photographer who died in 1984.

Matter and his wife, Mercedes, were longtime friends of Pollock and his wife, the painter Lee Krasner. The two couples also owned nearby homes on Long Island.

Since then, however, questions about the Pollock works have exploded into a full-blown controversy, complete with dueling experts, disputed scientific studies and threats of legal action against dissenting critics and scholars. The uproar has caused at least two museums — the Guild Hall museum in East Hampton and the Everson Museum of Art in Syracuse, N.Y. — to cancel exhibits of the would-be Pollocks.

One museum, though, is forging ahead.

On Saturday, Boston College’s McMullen Museum of Art will put more than two dozen of the disputed Pollock paintings on display. The show, “Pollock Matters,” marks the first time most of the controversial works will be on public view since their “discovery” in 2002 by Herbert Matter’s son, Alex.

According to a museum press release, the exhibit “will explore, for the first time the artistic relationship between famed American Abstract Expressionist painter Jackson Pollock and noted photographer and graphic designer Herbert Matter.” In particular, the show will focus on “the crucial role that Matters’ Matter’s technical innovations played in helping stimulate Pollock’s radical artistic conception.”

STILL, THE CONTROVERSY surrounding the paintings has clearly had an effect.

Museum officials, including McMullen director Nancy Netzer, have declined to discuss the exhibit until after it opens over the Labor Day weekend. The no-talk policy also includes the show’s curator, Ellen Landau, a Pollock scholar who initially declared the Pollocks authentic, then seemed to back away from her findings in face of questions from other experts. Outside scholars who helped with the exhibit, or who contributed essays to the show’s catalog, have also been asked not to talk about the show.

Not surprisingly, the decision to impose what amounts to a gag order on the exhibit has raised some eyebrows, especially since the museum is part of a larger academic institution.

“It’s definitely unusual,” says RISD Museum director Hope Alswang. “Normally, you’re trying to do everything you can to get people talking about an exhibit. Here, they seem to be trying to deliberately dampen people’s expectations. Then again, maybe it’s a brilliant P.R. move. They know everybody is going to be talking about the show, so by not talking about it, they generate even more interest.”

At the same time, Alswang applauds the museum’s decision to show the disputed paintings.

“Under the circumstances, I think it’s a very brave thing to do,” she says. “And if they can get people thinking and talking about Jackson Pollock, a towering figure in American art but someone whose work many people still dismiss or misunderstand, then all the controversy will be worth it.”

McMullen spokeswoman Naomi Blumberg says the museum’s no-talk rule reflects the difficulty of discussing complex issues of attribution and authorship in the midst of controversy.

“One thing that’s become clear over the past few months is that it’s very hard to talk about these artworks in a vacuum,” Blumberg says. “A lot of hard work and research has gone into this show. All we’re saying is, ‘Let’s wait until the show actually opens before we start talking about it.’ ”

“POLLOCK MATTERS” WILL include more than just the two dozen small “drip paintings” that have stirred most of the controversy, according to the museum’s press release. In addition to the disputed Pollocks, the show will feature works by both Herbert and Mercedes Matter. Several Pollock paintings whose pedigrees are not in question will also be displayed, along with works by Krasner.

Tantalizingly, the release also says the show will include several artworks by Pollock, Krasner and the Matters that have been discovered since the controversy began. In all, the show will feature some 150 artworks.

Still, it’s the purported Pollocks that most visitors will come to see. And even with reams of new research, it’s hard to see how “Pollock Matters” can dispel many of the doubts and suspicions that have surfaced in recent years.

Those doubts include questions about how the artworks were found, how they were handled after their “discovery,” whether they were created by Pollock himself or someone trying to mimic his style, and whether some of the pigments found on the paintings were even available during Pollock’s lifetime.

Financially and artistically, the stakes couldn’t be higher.

Though mocked during his lifetime as “Jack the Dripper,” Pollock is now considered one of the greatest artists of the 20th century. His trademark “allover” style, with its looping skeins and swirls of paint, is as recognizable to many people as a Picasso portrait or an Andy Warhol soup can.

And as Pollock’s reputation has grown, so have prices for his paintings. Last fall, a private collector (rumored to be music mogul David Geffen) paid $140 million for one of Pollock’s largest canvases, No. 5, 1948. The price is believed to be the highest ever paid for a painting.

NONE OF THE DISPUTED Pollock works come close to No. 5, 1948 in size. Most are painted on small pieces of cardboard. Some consist of little more than a few drops of paint, while others display the layered loops and swirls of pigment that are typically associated with Pollock’s mature work.

Still, if the paintings do turn out to be authentic, they would be worth a small fortune. One estimate placed the value of the works at roughly $1 million — each.

Unfortunately, attempts to authenticate the paintings have only whipped up more controversy. Pollock experts who have examined the works have come to radically different conclusions, with some, like Landau, favoring a Pollock attribution and others dismissing the paintings as fakes or copies.

Meanwhile, the case against the paintings has been bolstered by several scientific studies. Last year, an analysis by Richard P. Taylor, a physics professor at the University of Oregon, concluded that the looping patterns in the disputed paintings showed “significant discrepancies” from those in known Pollock works. Taylor, who examined six of the paintings using fractal geometry to look for telltale patterns, also suggested that more than one artist may have created the disputed works.

“That’s either due to one person who is extremely varied,” Taylor said in an interview with the New York Times, “or it’s due to a number of different artists.” Either way, Taylor concluded, the disputed paintings showed none of the characteristic patterns found in genuine Pollock paintings.

More recently, an analysis of three of the disputed paintings by researchers at Harvard University found that some pigments had not been available during Pollock’s lifetime. Using an array of advanced techniques, the researchers found that one work contained a paint not available until 1971 while another contained a paint that wasn’t introduced commercially until 1986. Pollock died in 1956.

TO THOSE WHO THINK the paintings are genuine, such findings are challenging but hardly conclusive.

They point to the close personal and artistic ties between Jackson Pollock and Herbert Matter, both of which are a matter of historical record. Is it so hard to imagine, they ask, that Pollock might have given his longtime friend a small batch of his paintings as a gift or for safekeeping?

They also point to the way the paintings were found — in a storage locker rented by Matter and filled with his personal belongings. When the locker was opened in 2002, Matter’s son Alex says he found the paintings wrapped in a piece of brown paper inscribed with his father’s handwriting. According to Alex, the handwriting identified the contents as “32 Jackson experimental works (gift & purchases).”

In a recent interview with the Cleveland Plain Dealer, Alex Matter questioned why anyone would bother to fake so many small paintings, especially when museums and collectors prize big Pollocks.

“Why would somebody try to do fakes of 32 paintings instead of one big one? It just doesn’t make sense. And why do experimental pieces? Why would somebody do it? It’s just ridiculous.”

Supporters of the paintings have also raised questions about the techniques used by scientists like those at Harvard and the University of Oregon. Fractal analysis, they note, is still an experimental technique, at least when it comes to studying paintings. And both the Oregon and Harvard studies were based on relatively small samples — six paintings in the case of the Oregon study and three at Harvard.

What’s more, the results of the Harvard study might have been tainted by an extensive cleaning and restoration program the paintings underwent shortly after they were discovered in 2002. In an attempt to stabilize the paintings, restorers may have introduced new pigments or chemical binders.

But Narayan Khandekar, an art-conservation specialist who participated in the Harvard study, said that was unlikely. In an interview this week, Khandekar said the Harvard team knew the paintings had been restored and took that into account during their tests.

“In our view, the fact that the paintings might have been subjected to some kind of restoration procedure prior to testing was not important,” he says. “It didn’t affect our analysis.”

Khandekar also said all three paintings examined by the Harvard team contained multiple layers of paint that were not available until after 1960. “We didn’t just look at the surface of the paintings,” he said. “The post-1960 materials were found at different layers throughout the paintings.”

Meanwhile, another scientific study involving a much larger group of the disputed paintings has been blocked by lawyers representing the paintings’ owners, including Alex Matter. That study was conducted by Orion Analytical, a research firm headed by Williams College professor James Martin.

No doubt some of the questions swirling around the disputed Pollocks will be answered once “Pollock Matters” opens on Saturday. But don’t expect closure any time soon.

“Pollock Matters” runs from Sept. 1 to Dec. 9 at the McMullen Museum of Art at Boston College. The museum is located on the first floor of Devlin Hall (140 Commonwealth Ave.) in Chestnut Hill, Mass. Museum hours are Monday-Friday 11-4 and Saturday-Sunday noon-5. Admission is free. For more information, call (617) 552-8100.

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