That’s what curator Thea Liberty Nichols calls the late artist Christina Ramberg, who will get a retrospective at the Art Institute of Chicago starting April 20. Ramberg was an artist and a teacher, but, as Nichols learned from months sifting through her ephemera — diaries, postcards, 35 mm slides, a doll collection — she was also a kind of historian. The objects that inspired Ramberg “didn’t exist in a library, or in
