In March, eight exclamation points marched across the back wall of the Grand Palais at Akris's fall 2019 ready-to-wear show in Paris, exuberant punctuation in the all-white room. Those exclamation points came from a 2006 work by the late artist Richard Artschwager and were made of horsehair, a material associated with upholstery rather than art.

In his nearly 40 years as Akris creative director, Albert Kriemler has frequently joined forces with artists. For past collections he has worked with 103-year-old modernist painter Carmen Herrera, contemporary photographer Thomas Ruff and minimalist architect Sou Fujimoto. “It’s really always based in my case on my personal experience with the artist,” Kriemler says. He works only with the artist’s approval. “You do it with the green light,” he says.

For the fall 2019 collection, it was Artschwager’s turn. Kriemler had used horsehair for the brand’s signature folded Ai bag a decade ago, but this time, taking his cue from Artschwager, the designer has incorporated it into the new collection as inlays, pocket edges and cuffs on blouses.

Other artist-designer collaborations that surfaced during the fall 2019 shows: Stella McCartney sent multiple looks down the Paris runway adorned with necklaces and belts made of wrapped and woven yarn by Sheila Hicks, an 84-year-old fiber artist who received a retrospective at the Centre Pompidou in 2018. A couple of weeks earlier in New York, designers Adi Gil and Gabriel Asfour incorporated scraps of discarded paintings by their neighbor, artist Stanley Casselman, into the fall collection they showed at the Guggenheim Museum.

Fashion and art have a long history together. In 1937 Salvador Dalí adorned a dress by Elsa Schiaparelli with a hand-painted lobster, and Wallis Simpson wore it in Vogue. Yves Saint Laurent sent A-line shift dresses divided by black lines into white and primary-colored squares in an homage to the paintings of Piet Mondrian in 1965. At Comme des Garçons, Rei Kawakubo created stretchy, padded gingham garments as an homage to choreographer Merce Cunningham in 1997.

But traditionally the influence tended to flow in one direction, with the commercial creatives of fashion taking inspiration — and sometimes just surface patterns — from artworks. Today, players in both art and fashion say that the line between their fields has become blurrier, as more artists embrace fashion as a means of reaching a wider audience. They’re recognizing that “fashion permeates culture in much knottier, more immediate and mass ways than most fine art, which is usually confined to a much smaller audience within museums and galleries,” says Michelle Millar Fisher, the Louis C. Madeira IV assistant curator of European decorative arts and design at the Philadelphia Museum of Art, and co-organizer of the Museum of Modern Art’s 2017 exhibition “Items: Is Fashion Modern?” MoMA’s first fashion show since 1944. “When artists hitch themselves to this phenomenon, when they align themselves with design and its direct access to everyday life, they benefit hugely,” she says.

But it wasn’t that long ago that the thought of mixing fine art and fashion was considered gauche. The retrospective of Giorgio Armani’s work at the Guggenheim in New York in 2000 was hugely controversial both for its content and for the timing of reported multimillion-dollar donation by the designer to the museum. “The whole art world went out of its mind, said it was so tacky,” says Kriemler. “Probably the Guggenheim people were visionary.”

In 2005, Raf Simons, who just over a decade later would become chief creative director for Calvin Klein, began a now-legendary collaboration with Los Angeles-based artist Sterling Ruby. Ruby, who has worked in ceramic, collage, quilt, paint, foam and steel, already wore a wardrobe he made himself; later he and Simons collaborated on a menswear line that included a hand-painted canvas parka much like Ruby’s own paint-spattered wardrobe.

For Ruby and Simons, the personal line between art and fashion quickly disappeared. “We were very interested in each other’s practices, and maybe we had the desire to do things that people could not see us doing,” Simons told an audience at Harvard in 2018. “I had art dealers saying, ‘This is a bad idea. Don’t do it,’ ” Ruby said on the same panel. But, he said, “I decided that we had been friends for such a long time and we had so many great discussions about what we can do.”

When Simons became creative director for Calvin Klein in 2016, the two men embarked on their biggest project, measured in square footage: the artist’s reimagining of the brand flagship on Madison Avenue. Once a minimalist space, Ruby painted it a saturated yellow and replaced the white built-ins with yellow scaffolding, hung with vintage quilts. Plush carpets and barlike fixtures in saturated blues and reds held shoes and stacks of tactile sweaters. My visit there in September 2017 felt like being inside an artwork — one not unlike the neon painted-steel monolith Ruby unveiled this past February outside Palm Springs, Calif., for the Desert X public-art exhibition. The store may be gone, but through art the idea can live on. That monolith, a little bit Stanley Kubrick, a little bit Donald Judd, has starred in influencer fashion shoots on Instagram.

For “Items” at MoMA, the curatorial team commissioned works from contemporary designers including Kerby Jean-Raymond of the label Pyer Moss and Zhi Chen of I-Am-Chen. Jean-Raymond worked next with artist Derrick Adams after they met on a panel organized by the Studio Museum in Harlem in conjunction with an exhibit of Adams’s paintings about pioneering African American fashion designer Patrick Kelly. “I was interested in the idea of fashion as an intellectual aesthetic, and in Patrick Kelly’s approach to design, which is leaning toward conceptual art rather than decor or surface,” Adams says. The two hit it off, and for his spring 2019 collection, Jean-Raymond collaborated with Adams on a series of clothing pieces that incorporate Adams’s paintings of his own family photographs.

The two were drawn together by a common interest in showing black leisure and family relationships. “I wanted to write us back in,” Jean-Raymond said in a video released before the clothes were shown in September 2018. “What does black life look like without the angst of racism and tragedy?” One of the most dramatic outfits was an allover beaded dress that depicts the christening of Adams’s baby cousin on a sparking, fluid column.

Adams describes artists as being “sacred with their material,” making just one of something. “But there are different tiers of audience, and a person who cannot afford one of my paintings may be able to buy a shirt with my painting on it.” That said, Adams isn’t interested in making multiples: “I don’t really think about sales when I think about my work. The fact that I am able to live off my work now is an extra added thing.”

Collaborations, while more common, still rarely last beyond a season or two. In January, Calvin Klein announced the Madison Avenue store would be closing for a fresh renovation in light of Simons’s departure from the company. But the experience appears to have stuck with Ruby, who in March announced a clothing line in an enigmatic Instagram post showing pattern pieces, paint splatters and crazy quilts, as if the artist were collaborating with himself. This move underscores the point that all the artists and designers I spoke to for this story were making: Why cut yourself off from an audience that seems hungry for visual ideas, whether they come from the museum or from a store?

Alexandra Lange is a writer in New York.