Color-blindness. (a) Color circles, normal and deuteranopic. (b) Jens (Johannsen) (1934–2010) was deuteranopic: Fields of Wheat (1980s). The painting (left) shows reddish roofs, but is otherwise predominately amber and blue-grey. Deuteranopic simulation (right) makes little difference except for loss of the roofs. (c) Baccio Bandinelli (1493–1560) was color-blind: Leda and the Swan (ca. 1512). The painting is beautifully drawn, but Leda's flesh is pasty without highlights. (d) Details of paintings by Raphael (1483-1520), who had normal vision: The Small Cowper Madonna (ca. 1505); and Bandinelli: Leda and the Swan. Deuteranopic simulation destroys the warmth of Raphael‘s flesh tones, but Leda is hardly affected by the conversion. Image details: Deuteranopic simulations through Coblis: www.color-blind.com/coblis (a) M F Marmor. (b) Oil on canvas (∼ 80 × 100 cm). Image provided by the artist; simulation by M F Marmor. (c) Oil on panel (128 × 101). © Chancellery of Paris Universities. Used by permission. Simulation, M F Marmor. (d) Raphael: Oil on canvas (full painting 60 × 44 cm). National Gallery of Art, Washington, DC: Widener Collection. Simulations, M F Marmor.