Does knowing Marie Laurencin’s sexual orientation, and Robert Smithson’s obsession with red, enrich our understanding of their creations? Yes, and no.

Robert Smithson, the pioneering land artist, repeatedly said that his art was a clear distillation of his essential self, and should be free of any biographical discussions, which he considered residual dross not worth examining. A work of art, he declared, was verifiable and substantial, while the essence of the artist is nebulous. He reveled in issuing gnomic pronouncements, proclaiming “Abstract art is not a self-projection, it is indifferent to the self.”

Smithson’s best-known work is “Spiral Jetty,” a 1,500-foot-long 1970 earthwork that juts into a corner of the Great Salt Lake in Utah. It appears as impersonal as an art piece can be. And yet, as Suzaan Boettger persuasively argues in her biography of Smithson, “Inside the Spiral: The Passions of Robert Smithson,” published earlier this year, the Sphinx-like monument — like Smithson’s other land art, sculpture and painting — secretly poses a riddle, with its answer buried in the artist’s life history.

Smithson died in a plane crash in 1973, when he was 35. As a graduate student researching earthworks in 1993, Boettger met with his widow, the artist Nancy Holt, who told her, “Now, you have to remember that Bob had a brother who died two years before he was born.” When she investigated, Boettger discovered that Harold Smithson had succumbed at the age of 9 to hemorrhagic leukemia, a horrific illness that was untreatable then. It manifested in children, she was informed by an elderly physician, as “bleeding out of their ears, eyes, nose, skin and bowels, bleeding internally, vomiting blood.” For Boettger, this fatal illness of the brother he was conceived to replace is a scarlet thread that runs through all of Smithson’s art.

Robert Smithson, shown here in Nov. 7, 1969, returned repeatedly throughout his career to the color red.Jack Robinson, via Hulton Archive/Getty Images

There can be no doubt that Smithson was obsessed with the color red. In his youthful paintings, which he disparaged in later life, Smithson depicted Christ’s Passion in black and white, using red as the sole accent. When determining where to construct “Spiral Jetty,” he considered only crimson bodies of water. He wrote in an essay that he chased reports of lakes “the color of tomato soup” and “wine-red water,” until he chose Rozel Point on the northeastern shore of the Great Salt Lake, largely because it was tinted red by algae and bacteria. It is highly plausible that Smithson’s color preference was influenced, even determined, by the family’s memory of his sanguinary doomed brother.

But once you admit that connection, a larger question emerges. Does it matter?

As the biographer of two artists, I have spent a lot of time pondering this problem. I strongly believe that in some cases, a viewer’s appreciation of the work is enriched by biographical knowledge. You don’t require the histories of Dora Maar or Marie-Thérèse Walter when viewing Picasso’s portraits of them, but it enhances your appreciation to see how Picasso depicted their character and transmuted his relationships into paintings. And even in his still lifes, explored in a memorable 1992 traveling museum exhibition, “Picasso and Things,” he arranged objects, fruits and flowers to comment on what was happening to him and in the larger world. Knowing that amplifies one’s comprehension of the art.

However, when it comes to nonfigurative artists like Smithson or his contemporaries and friends, including Donald Judd, Carl Andre and Sol LeWitt, who were deliberately squeezing the individuality of the artist’s hand out of their work, how helpful is it to learn about their parents or their romances? Their art seems a response to the aesthetic debates and sociopolitical concerns of their time, and not so much an outgrowth of their biographical individuality.

In his painting “Man of Sorrow (The Passionate),” from 1960, Robert Smithson portrayed Christ’s Passion in black and white, using red as the sole accent.Holt/Smithson Foundation/Licensed by Artists Rights Society (ARS), New York

Of course, the fact that the artist cultivates impersonality needn’t prevent personality from intruding into the work. But even more than with the allusions to bloodiness, I was uncertain what to make of Boettger’s reproduction of Smithson’s early homoerotic drawings and collages, which he exhibited only once in his lifetime. The subject of a doctoral dissertation by Jason Goldman, the pictures of naked men in alluring poses would be of little interest if the artist were anonymous. Even if, as Boettger writes, he patronized gay leather bars, it’s hard for me to see how that sexual proclivity shows up in his mature art, and apparently Boettger is of like mind, as she drops the subject after an early chapter devoted to it.

An exhibition that opens Oct. 22 at the Barnes Foundation in Philadelphia, “Marie Laurencin: Sapphic Paris,” is much more successful at establishing a link between an artist’s sexual orientation and her creations. Laurencin’s art invites, even demands, a biographical inquiry.

The show, curated by Simonetta Fraquelli and Cindy Kang, focuses on a biographical element — her lesbianism — which was not part of her professional self-presentation but appears, prudently coded, throughout her art.

Although Laurencin, who was born in 1883 and died in 1956, was famously the lover of the poet Guillaume Apollinaire (from 1907 to 1913), she was primarily attracted to women; even her portrait of Apollinaire, which dates from 1908, depicts him as softly feminine. In the circle of Picasso, who admired her painting and introduced her to Apollinaire, she dabbled in Cubism. Then World War I intervened. Having married a German baron, she moved for the duration of the conflict to neutral Spain. In her time away, she advanced her own style of painting.

“Cubism has poisoned three years of my life, preventing me from doing any work,” she said afterward, in a published interview in 1923. “ As long as I was influenced by the great men surrounding me, I could do nothing.”

Man Ray’s portrait of Marie Laurencin, 1925. “Her paintings celebrate female friendship without placing her subjects in sexual situations that would transgress social boundaries,” our critic says.Man Ray 2015 Trust/Artists Rights Society (ARS), NY/ADAGP, Paris; via MN-Grand Palais/Art Resource, NY

Even before the war, Apollinaire remarked in1908 that Laurencin’s work was “endowed with as many feminine features as possible.” Laurencin concurred. “If the genius of men intimidates me, I feel perfectly at ease with all that is feminine,” she wrote in middle age.

Living in Spain, away from the great men of Paris, she painted women without men, with delicate washes of color. She took back with her what she had learned. As a Vogue review in 1921 noted: “The art of Mademoiselle Laurencin is essentially feminine. It even possesses an exacerbated and quasi-obsessive femininity.”

Feminine, not feminist. Her paintings of elegantly garbed sylphs — in a tastefully modulated color range of pink, pale blue and gray — were so discreet and refined that they were popular with male collectors, including Albert Barnes. After a long eclipse, they may now be returning to fashion: They were featured in the Nahmad Contemporary booth at the Independent 20th Century art fair in New York in September. Her paintings celebrate female friendship without placing her subjects in sexual situations that would transgress social boundaries.

The excellent catalog to the Barnes exhibition does her no favors when it juxtaposes her portrait of Baroness Eva Gebhard-Gourgaud with Matisse’s vivid depiction in his Nice period of this well-connected art collector; and Laurencin’s decorous likeness of the lesbian cabaret singer Suzy Solidor pales alongside a sensuous one by Tamara de Lempicka. The writer Marguerite Yourcenar, also a lesbian and the subject of a Laurencin portrait, said that Laurencin transformed every sitter into “a very good little girl.”

Marie Laurencin, “The Does” (“Les Biches”), 1923; stage curtain design for the ballet “Les Biches.”Fondation Foujita/Artists Rights Society (ARS), New York/ADAGP, Paris; via RMN-Grand Palais/Art Resource, NY

Laurencin designed objects, interiors, wallpaper and especially theatrical sets. Most notably, she did the set and costume design for “Les Biches,” a 1924 ballet that Serge Diaghilev commissioned for the Ballets Russes, with music by Francis Poulenc. (The title, which translates as “The Does,” is also slang for “lesbians.”) Her theatrical designs are indistinguishable from much of her painting: charming and graceful, a throwback to the Rococo work of Watteau in the early 18th century.

When she did push the limits, however, her work becomes more interesting. In “Women With a Dove” (1919), she portrayed herself with her lover, the fashion designer Nicole Groult. In the painting, she is dressed androgynously, in a man’s white shirt and tie, with a pink bow around her waist. A bird is perched on the book she holds. Behind her, Groult, birdlike herself in a gray-feathered hat and cape, presses her lips to Laurencin’s shoulder. The scene is intimate, but the expressions of the two women are uneasy. I also admire “The Dance” (not in the show) from 1919, in which a woman in a pink dress presses her leg against her scantily dressed top-hatted dancing partner, while in the background an elegantly veiled woman with a playful white dog strums the guitar.

Her painting was a response both to the male-dominated avant-garde art in Paris and to her sexual identity as a woman who loved other women. It also reflected her need to earn a living (once she divorced her husband), which was slightly unusual in the fashionable lesbian circles of Paris. I don’t think you can assess her achievement without factoring in those elements.

Marie Laurencin’s “Women With a Dove (“Femmes à la Colombe”), 1919, in which she portrayed herself with her lover, the fashion designer Nicole Groult.Fondation Foujita/Artists Rights Society (ARS), New York/ADAGP, Paris; via RMN-Grand Palais/Art Resource, NY

Smithson’s life story, on the other hand, is detached from his work, much as the soil and other detritus he imported into a gallery to create what he called “nonsites” only faintly and distantly evoked their origins.

While it is fascinating from a personal point of view that Smithson returned repeatedly throughout his career to the color red, probably because he was haunted by the specter of the brother who died before he was born, much more crucial is his obsession with the way things break down through entropy, his love of ravaged industrial sites, his use of aerial perspectives and his preference for what was rough and splintered. These recurring features of his art are best understood by knowing what he read and saw, his conversations with other artists, his involvement in the politics of the day. It is a strange admission for a biographer to make, but I don’t believe his life story does much to illuminate his art.