A Toronto gallery’s show of rare Dadaist photos and collages, in a popular tourist destination, may, I hope, be a sign of a resurgence of interest in this relevant and instructive period. Erwin Blumenfeld: From Dada to Vogue, at the Corkin Gallery, is a small collection of pieces from one of the minor Dadaists, a German who fled that country during the First World War to the Netherlands and thence on to the United States, where he turned his avant-gardist techniques to commercial fashion photography. The pieces, obtained from his family, range from goofy humorous collages to elegant and quirky nudes. The show reminds us of a period when art was both politically dangerous and formally inventive, a combination that seems impossible now. It also illuminates how modernist avant-gardism bled into the commercial world and shaped the popular aesthetic of the 20th century.