For almost a half-century, the American sculptor Alexander Calder and the Spanish painter Joan Miro looked on each other as good friends. When apart, as they often were, they sometimes exchanged a letter or postcard of greeting. “A good smack on the butt for you,” wrote Calder in French in 1934. “A hug, kisses, and see you soon, you big stud,” wrote Miro in Spanish in 1945. They liked to embellish the postcards. Miro, for example, added underarm hair to the portrait of a Spanish dancer. But one thing they never did. Their correspondence has no discussion of theories or techniques or movements of art.

This lack of serious art talk makes sense. There are strong similarities in the work of Calder and Miro. Both artists have an impish quality, a sense of play, a love of adventure and a penchant for creating colorful spheres and biomorphs. But they did not try to imitate each other. Nor did they try to compete. They were simply at ease, like good buddies, and their art somehow fit together. There was no need for pronouncements.

This interplay of Calder and Miro is displayed in an unusual exhibition -- brimming with some of their finest mobiles and paintings -- that opened Oct. 9 at the Phillips Collection in Washington, D.C. Titled simply “Calder Miro,” the exhibition, which has already been shown at the Fondation Beyeler near Basel, Switzerland, closes in Washington on Jan. 23 and goes nowhere else in the United States.

Miro shows always attract me. One of the great privileges of my career as a foreign correspondent for the Los Angeles Times was the chance to interview Miro on his 85th birthday at his home and studio in Palma de Mallorca. Another correspondent and I spent several hours with him that day in 1978, and it was easy to be impressed by his energy, good feelings and shy smile. Yet, though I have seen many Miro shows over the years, this was the first time I had seen him sharing an exhibition with Calder.

Elizabeth Hutton Turner of the Phillips, the curator who conceived the show, believes the floating mobiles of Calder and the fanciful paintings of Miro complement each other. “Calder called himself a painter, not a sculptor,” she says. “He said he was drawing in space.” Calder was challenging the definition of a painting as something limited by the borders of a canvas. Miro, Turner adds, tried to do the same by painting figures as if they could float away from a canvas.

The artists met in Paris in 1928 when the 30-year-old Calder called on the 35-year-old Miro at his studio in Montmartre. Miro, born in Barcelona, had worked in Paris on and off for eight years and had already attracted attention with some of his finest work. His “Carnival of Harlequin,” in which he tried “to capture the hallucinations caused by my hunger,” was exhibited alongside the works of Pablo Picasso, Max Ernst and Giorgio de Chirico in the first exhibition of Surrealist paintings in 1925.

Although impoverished in those early days, Miro had a bourgeois sense of dress that made him stand out. When he walked on the streets of Paris, he would wear a bowler hat, bow tie, spats and a monocle. That sense never left him. Although he usually worked in coveralls, he put on a suit and a proper tie to receive us for our interview in 1978.

Calder, born in Lawton, Pa., was the son of a sculptor and a painter but turned his back on art and studied mechanical engineering at college. Engineering soon bored him, however, and Calder returned to the family trade by enrolling at the Art Students League in New York. He worked as an illustrator for the National Police Gazette, the most sensational tabloid of its day, and then joined the flock of American expatriates who rushed to Paris in the 1920s in hopes of making a name in art and literature. He earned his upkeep in Paris by making toys, producing shows of a miniature circus, and creating wire sculptures of celebrities and friends, including Miro.

Calder and Miro, two young bachelors, became close friends, meeting other expatriate artists at La Coupole, the large brasserie in Montparnasse. Miro, who sometimes boxed with Ernest Hemingway at the American Club, taught Calder how to box. Calder taught Miro how to dance.

In 1930, Calder visited the studio of the Dutch abstract painter Piet Mondrian. The studio was decorated like a Mondrian painting -- brilliant white walls adorned with rectangular strips of red, blue, yellow, black and white. The abstract colors impressed Calder. But he told Mondrian the impact would be greater if the rectangles could be made to move. Mondrian was annoyed at the suggestion. “No, it is not necessary,” he said. “My painting is already very fast.” But Calder mulled his own suggestion and eventually created assemblies of abstract, colorful pieces of sheet metal that moved in the air. The French sculptor Jean Arp dubbed the works “mobiles,” and Calder was en route to his special place in modern art.

Unlike Picasso with his string of mistresses and wives, Calder and Miro were family men who married young and remained with their wives for a lifetime. In 1929, Miro married Pilar Juncosa; they had one child, Maria Dolores. In 1931, Calder married Louisa James; they had two children, Sandra and Mary. Many of the letters between Calder and Miro include postscripts from their wives and daughters. During the interview with Miro, Pilar joined us in the living room as her husband was discussing his depictions of women. She interrupted and asked if we had ever noticed that, although his portraits of women were ugly, his self-portraits were quite handsome. Miro laughed and changed the subject.

By placing Calder’s mobiles and Miro’s paintings near each other in the exhibition, Turner reveals aspects that are sometimes unnoticed. I realized, for example, that the sphere in Miro’s “Man with Pipe” (1925), which I had seen before in Madrid, seems to hurtle through space. But Miro, of course, was not copying Calder. He finished the painting three years before they met.

In fact, some critics have implied that Calder often had Miro on his mind. In 1936, after Calder exhibited at the Pierre Matisse Gallery in New York, a critic in the New York World-Telegram wrote that Calder’s mobiles were “very much like Miro abstractions come to life.” Yet, though the current Phillips exhibition makes it clear that the artists shared a mood that makes their work compatible, the Calder mobiles are so graceful and unique that I never felt for a moment they were sculptured transformations of Miro paintings.

World War II kept the artists apart. Now married with children, both spent almost all the war years in their home countries -- the U.S. and Spain. During the war, Miro created his series of 21 paintings in gouache and oil on paper known as the “Constellations.” He painted a colorful whirl of stars, moons, birds, eyes, whiskers, spirals, dots, squares and triangles rushing through space in eerie balance. Carolyn Lanchner, curator of the Miro retrospective at the Museum of Modern Art in New York in 1993, called them one of the “miracles that art occasionally bestows.” Six are displayed in the Phillips show.

After the war, neither settled in Paris. Miro lived and worked in Barcelona and Palma de Mallorca, and Calder in Roxbury, Conn., but they visited each other from time to time and met in New York, Paris and elsewhere. In 1947, the artists were commissioned to provide pieces for the new Terrace Plaza Hotel in Cincinnati. Miro painted a 30-foot-long untitled mural on canvas for the wall of the rooftop restaurant; it is a joyful, color-drenched work, chock-full of playful monsters. Calder’s mobile, “Twenty Leaves and an Apple,” hung in the hotel lobby; it is one of his most intricate, balanced and beautiful works. The pieces, now owned by the Cincinnati Art Museum, dominate the final room of the Washington exhibition.

A voice of Spain

When I was based in Spain in the 1970s, Miro became a kind of poet laureate of the country’s transformation from the dictatorship of Gen. Francisco Franco to a democracy. Government institutions and private companies wanted Miro paintings, murals, mosaics and posters. A bank adopted a batch of colorful symbols from a mural as its logo. Miro seemed pleased to provide a poster for any cause that interested him, including the Barcelona soccer team. Spain became democratic awash in Miro colors and design.

In the 1970s, Calder and Miro were commissioned again to provide works for the same site -- the new east wing of the National Gallery of Art in Washington. Calder designed a 920-pound mobile to hang in the building’s atrium while Miro crafted (with fellow Spanish artist Josep Royo) an enormous tapestry for the opposite wall. But Calder died in 1976 at age 78, a year before the mobile was mounted. “Sandy, Sandy,” Miro wrote in a farewell poem, “your ashes caress the rainbow flowers that tickle the blue of the sky.” Miro, working without stop until the end, died in 1983 at 90.

During the press preview of the Phillips exhibition, I found myself drawn somewhat more to Miro’s paintings than Calder’s mobiles. But that was natural, reflecting more about my enthusiasm for Miro than about the exhibition. Yet I did not let my feeling for Miro blot out all the Calders at the Phillips exhibition. They are both wonderful artists. Putting the works of these old friends together is an inspired pairing that makes for a delightful show.