"Guillaume-Benjamin-Amant Duchenne (de Boulogne), The muscle of attention (left); Eyebrow contraction due to bright light (right), 1854-1856, albumen print, printed 1862, image: 22.1 × 16.7 cm (8 11/16 × 6 9/16 in.) mount: 40.3 × 27.7 cm (15 7/8 × 10 7/8 in.), W. Bruce and Delaney H. Lundberg Fund, in Honor of the 25th Anniversary of Photography at the National Gallery of Art, 2015.52.3"
