I winced when I got a press release for a new Georgia O’Keeffe documentary to be released “around Mother’s Day.” What does one have to do with the other? The artist, as the talking heads in Georgia O’Keeffe: The Brightness of Light know well, was never a mother at all. And yet, an expert appears in the film to say that, surely, she wanted to be one. It was her husband, Alfred Stieglitz, who declined. His daughter, from his first marriage, had succumbed to postpartum depression that left her institutionalized for the rest of her life. He didn’t want to go through that pain again. The evidence presented for O’Keeffe’s wanting children is simply this: she was a woman in her early 30s, a time when many women found themselves longing to have babies. Related Articles But O’Keeffe, of all people, was hardly most women. “I’m going to live a different life from you girls,” she told her classmates. “I’m going to give up everything to make art.” She did. So why O’Keeffe for Mother’s Day?…