Why John Sloan painted this lush scene of a woman in Union Square battling the rain

John Sloan was a Village resident and something of a voyeur in the early 1900s, discreetly watching from his window or walking nearby streets in search of scenes to commit to canvas. He never lacked material, finding inspiration in the ordinary: a woman hanging laundry, men drinking in McSorley’s saloon, the elevated train snaking through Greenwich Village, a stone-faced nun passing a shuttered theater. In 1912, it was the quick sight of a red stocking that compelled Sloan to create the lush, luminous “Spring Rain.” An article in the Journal of the American Medical Association from 2009, oddly, tells the story. “One day the unexpected glimpse of a red stocking in the rain caught his eye,” wrote physician Thomas B. Cole. “Stepping briskly along a path, a woman carrying an umbrella picked up her skirt to protect it from a puddle.” “Back in his studio, [Sloan] called the image to mind and painstakingly recreated the mood of Union Square on a blustery morning. . . . The eye-level…