Among the many gems in this trove (332 pieces) of artistic (Sudeks, Shores, Camerons, Hujars, Muybridges, snowflake microphotographs by Bentley, Blumenfeld’s “Blonde,” Capa’s “Bolshoi,”) industrial, scientific, commercial and legal photographic imagery in the intimate photo auction preview of The Knowing Eye: Photographs & Photobooks at Swann Galleries this week (auction today), I found myself returning to examine this ernest calling card, the tiniest item in the show.