Aleksandr Rodchenko, Portrait of Lyubov Popova, Undated, Rodchenko and Stepanova Archives (Moscow, Russia) © Rodchenko and Stepanova Archives (Moscow, Russia), Gelatin print, 1924, 20 x 16.7cm from Rodchenko and Popova: Defining Constructivism, February 12-May 17, 2009 at Tate Modern.