Jack Whitten photographed in his Queens studio on October 26, 2015. ©KATHERINE MCMAHON

Some artists use their long careers to perfect a style by creating variations on a theme, while others try to keep up with the times by continually doing something new. Jack Whitten was the latter kind of artist. By the end of his life, he had experimented with formalist painting, abstract portraiture, and even mystical visions of current events. “I want a worldview that will teach me how to conduct myself in this new world order,” he told ARTnews in an interview for a profile on the occasion of a traveling retrospective. “That’s what I’m working on”—and it was something he continued doing up until the end.

Whitten, whose process-based canvases pushed abstraction into new territory, has died at age 78, according to his gallery Hauser & Wirth. “It is with great sadness that we confirm the passing of Jack Whitten,” Marc Payot, a partner and vice president at the gallery, said in a statement. “He was a remarkable man—an artist of endless inventiveness, originality, and honesty, as well as a wonderful friend. His intelligence, compassion, and love for life have influenced all of us who knew and worked with him. Our hearts are with Jack’s family at this time.”

As with many painters whose style matured during the late 1960s and early ’70s, Whitten’s career wasn’t widely recognized until the past few years. But today, when Whitten’s visually seductive paintings appear in major museum shows, it has become difficult to imagine a history of abstract painting without his work.

Jack Whitten, April’s Shark, 1974, acrylic on canvas. ©JACK WHITTEN/COURTESY THE ARTIST AND HAUSER & WIRTH

Starting in the early ’70s, Whitten engineered new extrapolations on Abstract Expressionism. For a series known as the “Slab” works, Whitten utilized an unconventional process for which he would lay the canvas on the floor, drag a squeegee across to mix his color, and then let the paint dry. Paint was piled on as much as a quarter-inch thick in many of them, and all of the tones Whitten chose were left visible. With their warped, colorful forms and their unclear geometries, they resemble long-exposure photographs of things in motion.

By that point, Whitten had eschewed using oil, instead opting for acrylic paint, which dried faster. In doing so, Whitten relinquished some control over his canvases, leaving the final results to chance in some respects. To test the ways that time and tools affected the painting process became Whitten’s mandate.

Some of these “Slab” works appeared at a 1974 solo exhibition at the Whitney Museum in New York—an unusual fate for a black painter who was relatively unknown in the art world. At the time, Whitten’s style was unfashionable. Much of the New York art world had focused on movements that were believed to have more intellectual heft, like Minimalism, Conceptualism, and, later, the workings of the Pictures Generation. Painting had gone out of style, and yet Whitten continued doing it for his entire career, occasionally making forays into sculpture. (Some of his sculptural works were recently on view at Hauser & Wirth in New York.)

Other works by Whitten made use of unconventional tools and materials. In a series from the mid-’70s based on the Greek alphabet, Whitten placed metal sheets beneath his canvases, on which he applied wet acrylic that he then rubbed with pure powdered pigment. Through the process, Whitten was able to create textured canvases in which gray forms appear to hover.

In later works, Whitten came up with a mosaic-like method for applying paint. He would let acrylic dry, crack it into squarish chips, and then combine it to conjure images of people and objects that were important to him. Sometimes, what was being represented is not obvious: a series known as the “E Stamps,” from the mid-2000s, eulogized figures in Whitten’s life, like the curator Marcia Tucker and the painter Harvey Quaytman, through patterns that resemble postal codes that appear on mailed packages. An ongoing series begun in the ’90s known as the “Black Monoliths” memorialized pioneering African-Americans, like Ralph Ellison and Amiri Baraka, without ever showing their faces.

Jack Whitten, Black Monolith, II: Homage to Ralph Ellison The Invisible Man, 1994, acrylic and mixed media on canvas: molasses, copper, salt, coal ash, chocolate, onion, herbs, rust, eggshell, razor blade. ©JACK WHITTEN/COURTESY THE ARTIST AND HAUSER & WIRTH

Ethereal and oftentimes mystical, Whitten’s paintings came out of inquiries into philosophical, scientific, and mathematical concepts. The chipped-paint technique in the “E Stamps” works, for example, often makes his work shine, and it sprang from reading up on the physical properties of light. “We know now that light occurs in extremely small particles,” he once told ARTnews. “That’s what allows us to see—those little fucking photons bouncing around your retina, and blam-o, I can see!”

Whitten was born in 1939 in Bessemer, Alabama. A formative element of his upbringing was the racism he experienced there—he often referred to the segregation he experienced as “American apartheid.” When he went to college at Southern University in Baton Rouge, Louisiana, he became involved in the civil rights movement, staging sit-ins on campus and even peacefully closing the school briefly. In 1960, having tired of the South’s racism, Whitten left for New York on a Greyhound bus. He went to Cooper Union and graduated in 1964.

Unlike many artists at the time, Whitten was less interested in gestural abstraction than he was in something he would later term “conceptual painting.” He had in mind a specific phrase: “The image is photographic, therefore I must photograph my thoughts.” His series of “Head” paintings, some of his first mature works, offered wispy forms that look like specters appearing out of the dark. Crafted using a mesh-like fabric, the works confused his gallerist at the time, Allan Stone, who instead showed Whitten’s brushy, chaotically composed abstract oil paintings inspired by the civil rights movement.

Jack Whitten, Apps for Obama, 2011, acrylic on hollow-core door. ©JACK WHITTEN/COURTESY THE ARTIST AND HAUSER & WIRTH

For much of Whitten’s career, his work went unrecognized to large segments of the mainstream art world. But the inclusion of his paintings in a 2006 exhibition, “High Times Hard Times: New York Painting 1967–1975,” helped occasion a change. In 2014, the Museum of Contemporary Art in San Diego, California, hosted his first major retrospective which later traveled to the Wexner Center for the Arts and the Walker Art Center. A 40-work survey of his sculptures will open in April 2018 at the Baltimore Museum of Art, and will later travel to the Met Breuer.

By the end of his career, Whitten had started exploring digital technology, creating works such as Apps for Obama (2011), which might be considered a vision of Barack Obama’s iPad. The painting made use of Whitten’s beloved acrylic chips—an age-old technique that was here rendered new. Where Whitten’s work might have gone next will continue to intrigue, especially since Whitten himself often didn’t know. He was fond of quoting a sentiment that Stone frequently cited to him: “There’s no destination, it’s only the journey.”