Harry Callahan, Camera Movement on Neon Lights at Night, 1946, dye imbibition print, printed 1979, National Gallery of Art, Washington, Corcoran Collection (Gift of Richard W. and Susan R. Gessner) 2015.19.4192 (nga.gov)
Harry Callahan, Detroit, c. 1943, dye imbibition print, printed c. 1980, National Gallery of Art, Washington, Gift of the Callahan Family 2011.95.40 (nga.gov)
A passionate experimenter and a technical master, he was an early champion of the prized dye imbibition process of the 1930s. (artsy.net)