Murray Dessner, 77, a tall and handsome painter whose canvases were suffused with light and color and who deployed a keen and supportive critical judgment to the benefit of generations of students at the Pennsylvania Academy of the Fine Arts, died Saturday in Philadelphia.

His wife of 27 years, Linda, said the cause was cancer.

Mr. Dessner was born in South Philadelphia, attended the academy in the 1960s, and began teaching there in 1970, becoming one of the most respected and beloved faculty members until illness forced his retirement at the end of 2011.

"He was a wonderful, wonderful guy," said the painter and filmmaker John Thornton, who studied with him in the 1970s. "He was very encouraging, but honest. You just felt warmly embraced around him. You couldn't beat him as a teacher."

Painting was Mr. Dessner's life, and public engagement with his work appears to be not only in full flower right now, but growing. A show of recent paintings opened in January at Old City's Rosenfeld Gallery. Another, also of recent work, opens Oct. 5 at the Somerville Manning Gallery in Greenville, Del. "Four Visions/Four Painters: Murray Dessner, Bruce Samuelson, Elizabeth Osborne, and Vincent Desiderio" opens Oct. 6 at the Philip and Muriel Berman Museum of Art at Ursinus College.

Most inclusive and sweeping will be the Woodmere Museum of Art's "Murray Dessner: A Retrospective," which opens Oct. 13 and runs through Jan. 6. Linda Dessner said her husband continued to paint after retiring, and the Woodmere exhibition will follow the evolution of his work from the 1960s into 2012. "It's an amazing retrospective," she said.

The painter Elizabeth Osborne, one of Mr. Dessner's first teachers at PAFA in the early 1960s, when he entered after two years of drawing and painting at the Fleisher Art Memorial, said he "had a passion for trying to express color and light, and in the end he really got it."

"He was doing his best work when he died," she said. "It is just a heartbreak."

Inquirer art critic Victoria Donohoe called Mr. Dessner's paintings on view at Rosenfeld earlier this year "the strongest" she had ever seen. "Featuring both brilliant and pale hues and few deep tones, some of these abstractions . . . are canvases of monumental scale, in which the ultimate triumph belongs to color," she wrote.

His work is in the collections of the academy, the Philadelphia Museum of Art, Moore College of Art and Design, and museums and collections around the country.

Mr. Dessner was born in Philadelphia in 1934, but after his mother's death when he was 2, he and his brother went to live with an aunt and uncle in Pennsylvania's coal country. They eventually returned to Philadelphia, however, and he attended Bok Technical High School.

Mr. Dessner loved to draw and paint, but did not aspire to a career in art. Still, as a young man he spent two years honing his skills at Fleisher, where instructors encouraged him to apply for admission to the academy.

At PAFA, he went on to win two prestigious traveling scholarships and make many lifelong friends, including Osborne, the filmmaker David Lynch, the painter Tom Palmore, and a host of others.

"He couldn't believe a kid from South Philly could go to the academy," Linda Dessner said. "It was a wonderful group that jelled, and they respected each other immensely."

"It changed his life," said Jessie Burns, daughter of Mr. Dessner's friend C.K. Williams, the poet. She described the artist's presence as "incredible."

"He wasn't just a nice guy," she said. "If he was in your life, your life was changed. He was one of those enormous people."

In 1967, while on a traveling scholarship, Mr. Dessner visited the Greek island of Patmos and fell in love with it, returning almost every summer for the rest of his life. Like many artists before him, he became absorbed by the Mediterranean light and the ability of Renaissance and post-Renaissance masters to convey meaning through it.

In the same way, his work became an exploration of light and color that sought to transcend both. He wanted to mesmerize viewers with what they were seeing. His ambition, he once said: "How wonderful can I get it so you just want to look at it?"

Aside from his wife, Mr. Dessner leaves no survivors. He was predeceased by his brother, Teddy.

There will be no funeral, but plans are being made for a public remembrance, Linda Dessner said.

Earlier this year, after illness had forced his retirement from PAFA and he knew it was progressing, Mr. Dessner reflected to Thornton: "When I was teaching, I used this statement by van Gogh. They asked him, how do you become creative? He said, patience, energetic work, and courage.

"And I kept thinking, that was something you tell students. But I realize now it's something you should always keep telling yourself."