Nobel Prize–winning German physicist (1858–1947) who pioneered the understanding of quantum theory. Vintage matte-finish 2.5 x 3.5 photo of a reading Planck on its original 4.5 x 7 presentation mount with printed sentiment sending thanks for good wishes received on his 80th birthday, signed “M. Planck” with a lengthy inscription in German and dated June 15, 1938. A hint of very subtle soiling and water spot touching year of date, otherwise fine condition. Auction LOA John Reznikoff/PSA/DNA and R&R COA.
