On July 9, 1962, a little-known artist named Andy Warhol opened a small show at the Ferus Gallery in Los Angeles. His head-scratching subject: Campbell’s Soup. Each of his 32 paintings portrayed a different flavor in the lineup, from Tomato to Pepper Pot and Cream of Celery.

For Warhol, not quite 34 years old, it was his first solo painting exhibit. By then, he’d spent almost a decade as a top commercial artist, working with high-end advertising clients like Tiffany & Co. and Dior. But he was determined to become a “real” artist, recognized by museums and critics alike. His secret weapon? The emerging “Pop" art style.

Pop turned traditional art upside down. Instead of portraits, landscapes, battle scenes or other subjects that experts thought of as “art,” artists like Warhol took images from advertising, comic books and other bits of popular culture—the “pop” in Pop art. They used humor and irony to comment on how mass production and consumerism had come to dominate so much of American life and culture. Abstract artists of the 1950s like Jackson Pollock may have glorified themselves as creative, individualist geniuses, but Pop artists of the 1960s took the opposite approach. They tried to smooth over or eliminate all traces of their own art-making processes—like brush strokes—so that their work seemed almost mechanical, like the mass-produced subject matter it portrayed.

Almost. To make the “Campbell’s Soup Can” paintings, Warhol projected the image of a soup can onto his blank canvas, traced the outline and details, then carefully filled it in using old-fashioned brushes and paint. For consistency, he used a hand stamp to make the fleur-de-lys pattern around each label’s bottom edge, but he didn’t always get it right. Small details—tiny splashes of red on the Tomato Soup painting, the unevenly applied fleur-de-lys stamp on others—betrayed the paintings’ handmade origins. In using fine art techniques to depict an everyday manufactured object, Warhol captured an essential contradiction in Pop art. Although they were supposed to look like they’d been made mechanically, every painting was slightly different—and not only in the flavor on the label.

But there’s one thing all 32 paintings have in common. Instead of detailing the intricate medallion at the center of every can's label—representing the “gold medal of excellence” that Campbell’s Soup won at the 1900 Paris Exposition—Warhol substituted a plain gold circle. “Is it simply because other paints don’t stick well on top of gold? Because getting the medals just right would take too much work and might never look good, anyway?” pondered Warhol biographer Blake Gopnik. “Did he just like the gold circle’s graphic punch?”

Graphic punch—and an air of nostalgia—may be two reasons Warhol chose Campbell’s product line as his Pop icon. The classic label design had changed little since its turn-of-the-20th-century debut, including the homey, cursive "Campbell's" script, which according to a company archivist, was very similar to founder Joseph Campbell's own signature. And Warhol himself had grown up with Campbell's soup. “I used to drink it,” he said. “I used to have the same lunch every day for 20 years.”

When Warhol’s show opened in 1962, Pop was just getting started. People had no idea what to make of art that was so different from everything that art was supposed to be.

For one thing, Irving Blum, one of the owners of Ferus Gallery, chose to display the paintings on narrow shelves running the length of the gallery, not unlike a supermarket aisle. “Cans sit on shelves,” he later said about his installation. “Why not?”

The show didn’t make the splash Blum and Warhol hoped for. In fact, what little response that came from either the public or art critics could be harsh. “This young ‘artist’ is either a soft-headed fool or a hard-headed charlatan,” one critic wrote. A cartoon in the Los Angeles Times lampooned the paintings and their supposed viewers. “Frankly, the cream of asparagus does nothing for me,” one art lover says to another, standing in the gallery. “But the terrifying intensity of the chicken noodle gives me a real Zen feeling.” An art dealer down the street from Ferus Gallery was even more biting. He arranged real cans of Campbell’s Soup in his window, along with a sign that read: “Do Not Be Misled. Get the Original. Our Low Price – Two for 33 Cents.”

Despite it all, Blum managed to sell five paintings—mostly to friends, including actor Dennis Hopper. But even before the show closed, he did an abrupt about-face. Realizing the paintings worked best as a complete set, Blum bought back the ones he’d sold. He agreed to pay Warhol $1,000 for all 32 paintings, paid over 10 months. Warhol was thrilled—he’d always thought of “Campbell’s Soup Cans” as a set. For both artist and dealer, the decision was a “canny” move that would pay off big-time down the road.

Once the public and the critics got over their shock, they warmed to Warhol’s soup cans. For one thing, they made art fun. How hard could it be to understand a painting when the original was probably on your kitchen shelf? Critics started to see the sly, ironic humor in Warhol’s “portraits” of Scotch Broth and Chicken Gumbo. And Blum’s decision to keep the paintings together heightened their impact.

The show at Ferus Gallery marked a turning point in Warhol’s career. After the “Campbell’s Soup Cans,” Warhol switched from painting to silkscreen printing, a process that produced more mechanical-looking results and allowed him to create multiple versions of a single work. His reputation continued to rise. By 1964, the asking price for a single soup can painting not in Blum’s set had shot up to $1,500, and New York socialites were wearing paper dresses in a soup can print—custom-made by Warhol himself—to gallery openings.

It didn’t take long for Campbell’s Soups itself to join the fun. In the late 1960s, the company jumped on the then-popular fad for paper dresses, coming out with the Souper Dress, a kicky little number covered in Warhol-esque soup labels. Each dress had three gold bands at the bottom, so the wearer could snip her dress to the ideal length without cutting into the soup can pattern. The price: $1 and two Campbell’s Soup labels.

Today, Warhol soup cans remain a pop culture icon, turning up on everything from plates and mugs to neckties, t-shirts, surfboards and skateboard decks. One of the most striking images involved Warhol himself—the May 1969 cover of Esquire magazine showed him drowning in a can of Campbell’s Tomato Soup.

In the end, Warhol’s soup cans were recognized as museum-worthy art, by no less than The Museum of Modern Art. In 1996, the museum bought the 32 paintings from Irving Blum as a combination gift and sale valued upwards of $15 million—a jaw-dropping return on his $1,000 investment in 1962. Even the Souper Dress has been declared a classic. In 1995—the year before the paintings went to MoMA—it became part of the collection of The Metropolitan Museum of Art.