How did artists such as Robert Rauschenberg combine real objects with painted surfaces?

Robert Rauschenberg pioneered the use of real-world objects in his art through what he termed "combines"—works that bridged the gap between painting and sculpture.12

Inspired by the Merz collages of Kurt Schwitters, Rauschenberg began incorporating heterogeneous items such as Coca-Cola bottles, traffic barricades, stuffed birds, and personal items like pillows and sheets into his work. In his notable piece Bed (1955), he stretched his own quilt and pillow over wood supports, hoisted them vertically, and applied paint in an ironic reference to Abstract Expressionism.12

Rauschenberg treated the picture surface as a "flatbed"—a concept described by critic Leo Steinberg—on which he could pin or attach these objects and images rather than attempting to unify them through traditional painterly criteria. Later, he further integrated imagery by using solvents to transfer newspaper and magazine photographs directly onto canvas, and eventually adopted silk-screen stencil techniques to apply photographic images, which he then unified compositionally with broad, expressive brushstrokes.21