It had been four years since the painter Robert Baribeau had a show in Manhattan. And before Wednesday night’s opening at the Allan Stone Gallery, before the guests arrived and the gallery was sparsely populated with interns, Mr. Baribeau confessed that his anxiety around openings had only mounted in three decades of showing work. “Maybe I need some art Viagra,” he said, his red-rimmed glasses still bearing a speck of paint.

Mr. Baribeau need not have worried. The supportive crowd of friends and collectors that soon arrived to see his exploration of pleasing and riotous work in a palette of bright jewel tones gave this gathering the feel of a family reunion rather than a high-voltage art opening.

The artist had driven in from his home in Stanfordville, N.Y., where he lives with his wife, Michiko, for most of the year. The couple met as college freshmen; she recalls him as a noisy, hard-partying charmer, who distracted her from her studies with continuous antics outside her dorm room, and later proposed marriage by the pulsing light of a beer vending machine in front of the Tokyo YMCA. “Real class,” Mr. Baribeau said. “I was better looking then.”

A few years later, Mr. Baribeau began another marriage of sorts, to Allan Stone, the irrepressible collector who began to represent the artist’s work in 1979. When Stone died in December 2006, his daughter Claudia took over as director, and continued her father’s legacy. She had known Mr. Baribeau for most of her life, witnessing the development of his work through the years, connecting to him and his family as part of the large extended family of her father’s gallery. Of the 29-year relationship to Mr. Baribeau, Ms. Stone said, “In today’s art market it’s unusual, but in the history of this gallery, it’s not at all unusual.”

This was Mr. Baribeau’s 10th solo show at the gallery, and he soon seemed entirely at ease. On view were nine mixed-media pieces featuring exuberant brushstrokes, collage, and gobs of paint on canvas; his three paintings of flowers were far quieter by comparison.

Ms. Stone sold several pieces quickly, and while she was expecting to tend to the interest of collectors throughout the evening, she insisted that the reception was more about celebrating than selling. “A dancer gets applause, a musician gets applause; this is his opportunity to hear that.”

Commerce continued nonetheless. Lawrence Klepner, a vice president of investments at UBS, spent some time considering one of the mixed-media works ($25,000, and, as all of the pieces were, labeled “Untitled”). “What you have on your walls these days is an important statement of who you are. The palette is very strong, and the textures are very special.” And yet he wouldn’t be doing business at the reception. “Mama said, ‘Don’t run for a bus,'” he said.

Kerry Connolly, a longtime friend of Ms. Stone’s and a regular at the gallery’s openings, said she preferred the paintings of flowers ($8,500). “I’m a lawyer, so not everything is accessible to me. But I love the flowers. Those are easy,” she said.

Sandra and Brian Barris have one of Mr. Baribeau’s pieces in their Greenwich home, but hadn’t met the artist until the reception. “He’s very outgoing,” Mrs. Barris said after having her photo taken with Mr. Baribeau. “He’s as dynamic as his paintings.”

In the comfortable warmth of the post-heat-wave sun, guests snacked on grapes and chips in the gallery’s courtyard amidst its collection of contemporary sculptures. For most of the guests, the opening was not one of many they would attend that evening, as they might on other nights in Chelsea or Midtown. “Everyone’s smiling,” the artist Bo Joseph said. “You don’t see that a lot.”

Until July 18 (113 E. 90th St., between Lexington and Park avenues, 212-987-1655).