Nobel Prize–winning German physicist (1858–1947) who pioneered the understanding of quantum theory. Matte-finish 2.5 x 3.5 photo affixed to a 4.5 x 7 mount with a printed message of thanks related to Planck’s eightieth birthday, signed on the mount “M. Planck” with a sentiment in German and dated June 1, 1938. Scattered light soiling and staining, otherwise fine condition. R&R COA.