Otto Dix, "The Art Dealer Johanna Ey," 1924, Oil on canvas. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn)

Otto Dix, Helene Lange, 1925, Charcoal on transparent paper. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn)

Max Beckmann, Marie Swarzenski, ca. 1927, Pastel on paper on cardboard. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn)

Otto Dix, "Alfred Flechtheim," 1926, Graphite and charcoal on thick transparent paper. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn)

Otto Dix, "Fritz Lehmann," 1920, Pencil and red chalk on paper. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn)

Otto Dix, "Dr. Paul Ferdinand Schmidt," 1921, Pencil on transparent paper. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bonn)

Max Beckmann, "Lilly von Schnitzler-Mallinckrodt," 1931 Pencil on paper. (Artists Rights Society (ARS), New York/VG Bild-Kunst, Bon)