Artist John Rummelhoff could draw "stamps" on envelopes with such skill that they fooled the postal system.

"They were whimsical," said his brother Tim, and so real-looking that many went through the mail. One caught the admiring eye of a postal employee who wanted to add it to his collection, triggering the discovery that it was fake — and a summons from a postal inspector.

But Rummelhoff wasn't deterred. "He kept sending them," his brother said. "That kind of thing appealed to him."

Those who knew him called him "brilliant" and "enormously talented," but also "mysterious" and "difficult." "He was an incredible artist with a troubled soul but a big heart," Tim Rummelhoff said of his brother, who died in his Minneapolis studio home in late October at 76.

Although he devoted his life to art, Rummelhoff resisted the label of artist, said Kim Matthews, an artist and longtime friend. "He believed that the word had been trivialized to the point of meaninglessness." When asked what he did for a living, he said, "I make things."

"He was crusty on the outside, soft on the inside," Matthews said. "He had lived a hard life, and he was guarded, but once you got to know him he was loyal and generous with his time, his materials and his knowledge."

Matthews considered him a mentor and brought him pieces she was struggling with, seeking his help and expertise. "I'd come back, and it would be wonderful," she said. "He had insane skill with spray paint."

Growing up in Minneapolis, Rummelhoff's talent was apparent at a young age. "He was always drawing," Tim recalled.

At 17, Rummelhoff left home and Patrick Henry High School to hitchhike to New York City. "He wanted to be an artist," Tim said. "Wild horses couldn't have kept him around."

By his early 20s, he had made a name for himself on the New York art scene, where his work attracted the attention of art dealer Louis K. Meisel, who signed him to his stable of paid artists.

Meisel was a leading figure in the photorealist movement, and Rummelhoff was part of its vanguard. His work was featured in Meisel's first "Photorealism" book and was displayed in museums, including the Smithsonian Aerospace Museum, and purchased by collectors such as Marlon Brando and Lauren Bacall.

Rummelhoff lived in Greenwich Village, hobnobbing with high-profile artists including Andy Warhol, who autographed a photo of himself superimposed on his iconic Campbell's Soup can at Rummelhoff's 1968 birthday party.

But "the excesses of being a star artist" took their toll, said Tim. "He wore out his welcome."

By 1979, Rummelhoff had returned to Minneapolis where he opened a studio and "reinvented himself," without the excess that had been his downfall in New York. He made his living selling his paintings and drawings, building picture frames and working with real estate agents to stage high-end homes with his work.

"He lived hand to mouth, always," said Matthews.

He could paint for 36 hours at a stretch. "Day and night were interchangeable," his brother said. "He was a bohemian artist till the day he died. He continued to create art."

Rummelhoff didn't own a computer or a car, preferring to walk or ride the bus, his brother said.

"He had a broad circle of friends who looked out for him," said Peter Watson, a friend and former neighbor now living in Mexico. "He was a curmudgeon, ornery, but he had a great sense of humor and a spark of genius. Some of his paintings and drawings took my breath away."

Matthews will miss "the kinship that we had through art," she said.

Rummelhoff is survived by brothers Tim and David and sister Kathleen Rummelhoff-Bursaw.