BEVERLY HILLS, Calif. — It's an antique collector's dream: buying an old box at a garage sale and discovering it contains famous lost works worth a fortune.

That's what Rick Norsigian said happened to him. Ten years ago, the Fresno painter stumbled upon a trove of 65 old glass negatives that he says have been authenticated as the work of famed nature photographer Ansel Adams, possibly worth $200 million.

"This is absolutely beyond what I thought," the 64-year-old said at a press conference held at a Beverly Hills art gallery on Tuesday. "I'm very lucky."

Norsigian's lawyer Arnold Peter said a team of experts who studied the negatives over the past six months concluded "beyond a reasonable doubt" that the photos were Adams' early work, and they were believed to have been destroyed in a 1937 fire at his Yosemite National Park studio.

"These photographs are really the missing link," he said. "They really fill the void in Ansel Adams' early career."

Adams is renown for his timeless black-and-white photographs of the American West, which were produced with darkroom techniques that heightened shadows and contrasts to create mood-filled landscape portraits. He died in 1984 at 82.

His photographs today are widely reproduced on calendars, posters and in coffee-table books. His prints are coveted by collectors.

Yosemite National Park fetched $722,500 for Ansel print "Clearing Winter Storm" at an auction last month in New York, a record for 20th century photography.

Norsigian, who works for the Fresno Unified School District, is already planning to capitalize on his discovery. He's set up a website to sell prints made from 17 negatives from $45 for a poster to $7,500 for a darkroom print with a certificate of authenticity. A documentary on his quest to have the negatives authenticated is in the works, as well as a touring exhibition that will debut at Fresno State University in October.

Representatives of Adams, however, said they're not buying Norsigian's claims.

"It's an unfortunate fraud," said Bill Turnage, managing director of the Ansel Adams Publishing Rights Trust. "It's very distressing."

Turnage said he's consulting lawyers about possibly suing Norsigian for using a copyrighted name for commercial purposes. He described Norsigian as on an "obsessive quest." ''We've been dealing with him for a decade," he said. "I can't tell you how many times he's called me."

Adams' grandson, Matthew Adams, who heads the Ansel Adams Gallery in San Francisco, said he reviewed Norsigian's authentications last fall and thinks they're stretches. Many photographers took pictures of the same places Adams did in that era, he said.

"There is no real hard evidence," he said. "I'm skeptical."

Norsigian bought the negatives from a man who said he had purchased the box from a Los Angeles salvage warehouse in the 1940s, bargaining the price down from $70 to $45. He saw they were of views of Yosemite but never suspected they might be Adams' works until someone mentioned they resembled the famed photographer's shots. "We got a laugh out of that," Norsigian said.

But the idea stuck with Norsigian and he started researching the photographer, eventually concluding they were Adams' works.

The shots are of places Adams frequented and photographed. Several shots contain people identified as Adams associates. Adams taught at the Pasadena Art Center in the early 1940s, which would account for the negatives being in Los Angeles. The negatives are the size Adams used in the 1920s and 30s and several have charred edges, possibly indicating the 1937 fire.

"You keep adding bits and pieces," Norsigian said.

For years, he tried to get them officially verified, taking them to experts at the Smithsonian Institution, the Getty Center and others, but no one would venture to authenticate them.

Three years ago, he met Beverly Hills entertainment lawyer Peter, who assembled a team of experts to review the negatives.

The key evidence came from two handwriting experts, who identified the writing on the negative sleeves as that of Adams' wife Virginia.

But Matthew Adams said there were inconsistencies in the handwriting and a lot of misspelled Yosemite place names. "She grew up in Yosemite. She was an intelligent, well read woman. I find it hard to believe she would misspell those names," he said.

Peter also hired a meteorologist who studied the cloud formation, snowdrift and shadows on one image and compared it with a similar photograph by Adams, concluding they were taken at the same location on the same day.

But Matthew Adams said those evaporation clouds appear every day and the snowdrift is on mountains 20 miles away. "I suggested carbon dating of the charring and the envelopes," he said.

Matthew Adams said it was unlikely his grandfather would have misplaced the negatives, especially after the devastating fire that destroyed 5,000 negatives — a third of his portfolio. "Ansel was very meticulous about his negatives," he said. "He kept them in a bank vault in San Francisco after the fire."

Beverly Hills art appraiser David W. Streets said he conservatively estimated the negatives' value at $200 million, based on current sales of Adams' prints and the potential for selling never-seen-before prints.

Turnage called that figure ridiculous because the value of Adams' work is in his darkroom handcrafting of the prints, and said the negatives are next to worthless.

"Ansel interpreted the negative very heavily. He believed the negative was like a musical score. No two composers will interpret it the same way," he said. "Each print is a work of art."

Norsigian is not fazed by naysayers. "Prove me wrong," he said. "This has been such a long journey. I thought I'd never get to the end. It kind of proves a construction worker-painter can be right."