In July 1932, Frida Kahlo ended up in Henry Ford Hospital in Detroit, where a complicated pregnancy came to a painful end, perhaps a miscarriage or the result of abortion. Her ability to have children may have been compromised by injuries from a violent bus accident in 1925, so it isn’t clear exactly what happened. But Frida’s husband, the Mexican muralist Diego Rivera, referred to the event as “Frida’s tragedy,” and a self-portrait Kahlo made shortly after shows her glassy-eyed, with a frightened and drawn expression.

The drawing appears in an absorbing exhibition at the Detroit Institute of Arts devoted to the year the two artists spent in what was then the industrial heart of America. “Diego Rivera and Frida Kahlo in Detroit” weaves together two narratives, the emergence of Frida as an individual and daring artist, and the creation of one of the last century’s great mural cycles, “Detroit Industry,” painted on the walls of a covered courtyard in the DIA’s new home, designed by architect Paul Cret.

But the show is about much more than the sojourn of two fascinating individuals in an unlikely place for both of them — Rivera was a communist, and Kahlo hated America. It is a self-conscious effort by the DIA to reintroduce itself to the larger art world, and reassert its presence as a vibrant institution after years of struggle and near-death experiences. The subject may be one of the most intriguing power couples in the history of 20th-century art, but the purpose is greater: to focus attention on the DIA and one of its greatest assets, a room some locals refer to as “the Sistine Chapel of industrialism.”

Evoking emotions

It is a powerful show that gathers strength as Kahlo’s work gains in complexity and depth. When the artists arrived in Detroit, Kahlo was working in a style clearly derivative of her famous and accomplished husband’s interest in Mexico folk art. And yet, while the earliest of Kahlo’s mature work in this exhibition show her working in Rivera’s shadow, she was clearly striving for different effects. A 1931 painting, “Portrait of Eva Frederick,” captures its subject facing forward, directly addressing the viewer, as in many of Rivera’s works, and it includes a cartoon-like scroll with text above the head, another nod to folk art. But it has none of the rigorous stylization of Rivera’s work, none of the blunt, slightly patronizing distance between the artist and subject. Eva Frederick may not be expertly rendered, but she is fully present as an individual.

Frida Kahlo’s “Self-Portrait on the Borderline between Mexico and the United States,” a 1932 oil on copper plate. (Courtesy of Manuel and Maria Rodriguez de Reyero)

If the early rooms feel sparsely populated with Kahlo’s work, it’s because she wasn’t yet fully committed to making art. A 1926 pencil drawing of the accident that severely injured her pelvic region suggests a child’s hand, yet with an intuitive sense of drama and narrative. A 1928 watercolor, “Small Mexican Horseman,” is diligent but naive, yet the colors are appealing. But things change while she is in Detroit, perhaps in response to an exhibition she had recently seen in New York, the landmark 1932 Surrealist Group Show, which featured Duchamp, Picasso, Dali and Joseph Cornell, and likely in response to her own physical and mental suffering.

The exhibition not only includes the self-lacerating painting “Henry Ford Hospital” — which depicts the loss of her pregnancy — but also a pencil sketch for the work. It is revelatory to see the two side by side. Both show a woman in a hospital bed, with the date and place inscribed on the bed rails. She lies naked and supine, yet connected by cords to small anatomical, zoological and industrial images, including a fetus or baby, a snail and a rendering of the pelvis. But from sketch to painting, the image improves and takes on depth. In the pencil drawing, the symbolic forms are rendered close to the bed, which floats in empty space; in the painting, they have been moved slightly away from the bed and the human form it contains, making room for a horizon line on which the artist has rendered the industrial forms of Detroit.

This inclusion of Detroit in a deeply personal image deflates any simplistic attempt to argue that while her husband was interested in the world at large, she was limited to the personal, the psychological and the traumatic. It’s a tempting simplification because it is partially true. Kahlo’s work organizes the mind and the emotions, while Rivera’s organizes social, historical and economic forces. But neither artist can be reduced to a formula: Kahlo pushes her work into social critique through the particulars of individual suffering, while Rivera was capable of great psychological subtlety in his portraits and self-portraits.

If at first it seems a conceit to weave together the thin strand of early Kahlo with the almost-too-muscular work of Rivera, the critical month of July 1932 suddenly transforms their relationship and art. Rivera started painting his murals only days after Kahlo’s pregnancy came to an end. In the exhibit, her hospital images share a room with two of his full-sized charcoal sketches for a long, rectangular panel of the DIA murals. The first version, which was discarded, is an agricultural scene, with husky men in caps bent to farmwork; the second, which prefigures what now appears on the walls of the museum, shows what looks to be a fetus sleeping in some kind of earthy, underground womb. Viewers of the mural, unaware of what happened to Kahlo, would naturally assume this symbolized man’s power over the earth, his capacity for regeneration and renewal.

Industrial themes

Rivera’s sketches for the Garden Court are on view for the first time in 30 years, and they bring the finished frescoes into new relief, placing them closer to the viewer, and focusing the attention on the complicated construction of the murals. Rivera concentrated on the production of cars, from beginning to end, with such fidelity to the industrial process that he was praised by engineers and auto barons for his mastery of the details. There’s a complex and engaging balance of flat, almost two-dimensional regions, and areas where the images seem to break through the wall they are rendered on, drawing the eye deep into the distance.

Rivera borrowed from the best, freely adapting forms familiar from religious and Renaissance painting, including a lower register of predella panels — as one might find on the bottom of a religious altar piece — in monochrome, cleverly disguised as part of a trompe l’oeil guard rail or barrier, yet another gesture that draws the eye in and delights with old-fashioned illusionism. Another religious reference was more controversial: At the top of the north wall, the artist depicted the wonders of medicine by representing an infant being inoculated. The horse and cow surrounding the baby reference the source of serum but also create a clear allusion to a manger scene. Balancing the panel in the same register on the left is a depiction of scientists making poison gas bombs.

Throughout the murals, one finds plenty to annoy the sensibilities of the bourgeois but little to enrage them. An amply proportioned woman with a cross around her neck looks like she is wearing a soldier’s helmet and suggests a stupid and ferocious aspect to the religion she represents. A group of men on the north wall seem to be pushing a cart, except for the lone African American among them, who is working at cross purposes. A panel on the south wall shows a group of dour women manufacturing pharmaceuticals, under the stern watch of an overseer spying on them through a rear-view mirror.

But Rivera’s Detroit imagery didn’t put his communism nearly so forward as his next big project, a mural at Rockefeller Center in New York City, which included a depiction of Lenin. Nelson Rockefeller was not amused and ordered it destroyed, one of the most appalling acts of philistinism in the history of modern art. There was plenty of controversy over the Detroit project, but Edsel Ford, the scion of the Ford family who paid out of his own pocket for the Detroit murals, wasn’t inclined to drama.

Which leads to the paradox of the DIA Garden Court: Was Rivera pulling his punches? Was he seduced by Henry Ford’s money and Edsel Ford’s amiability? Was he creating a fantasy rapprochement of industrial titans and happy laborers? He had no reason to believe in such illusions: Only weeks before Kahlo and Rivera arrived in Detroit, police in Dearborn, Mich., joined by security thugs employed by Ford Motor Co., fired on a crowd of thousands of unemployed workers, killing four, including a 16-year-old boy.

Like police today who kill unarmed African Americans, the perpetrators of the massacre at the Ford Hunger March were never punished. The martyrs of that crime are mostly lost to history, while Rivera’s murals are now the backdrop for crowds of well-heeled art lovers passing through a museum of cultural treasures. Rivera clearly believed that he could “infiltrate” the capitalist system and help reform it, or destabilize it, through art. He failed.

But at least he tried to assert the possibility of a better world. The thrill of his murals, like the gritty thrill of everything about Detroit, is its lingering appeal to the conscience: It was the labor movement, in militant cities like Detroit, that brought us the five-day workweek, sick leave, vacations, health-care benefits and a ban on child labor; much of this was bought with blood. All of this is in peril, today, as inequality explodes, as Americans lose faith in their police, their government and their economic system, and as a new breed of capitalists posits a new social contract — work until you drop, then die — which is no social contract at all.

This exhibition, like the museum it graces, gives hope for a new radicalism that will make us raw and alert to neglected possibilities in our circumscribed spiritual and political worlds. Kahlo dug into her own psyche to champion women and subvert the arbitrary rules of gender; Rivera sought to connect people across racial, geographic and class lines. Their actual marriage wasn’t happy, but the marriage of what they stood for has limitless potential.

The DIA recently emerged from a period of great danger, as creditors in the bankrupt city sought to sell its art to pay for pensions promised by the city. For an ugly period, it seemed a drama of art vs. people. Fortuitously, and through long and tortuous negotiations, a compromise was reached, and the DIA survives. Now it returns to vigor with an exhibition that demonstrates just how false, and misleading, a dichotomy between art and the working class really is. Both Kahlo and Rivera had rich and ready reasons to loathe America, during and after their Detroit chapter. But they left a legacy there that deserves to be seen by every American who still believes democracy gives us the power to make the world more humane, just and equitable.

Diego Rivera and Frida Kahlo in Detroit Through July 12. For more information, visit www.dia.org.