Collage played a pivotal role in the evolution of Cubism, and Cubism had, of course, a pivotal role in the evolution of modern painting and sculpture. As far as I know, Braque has never explained quite clearly what induced him, in 1912, to glue a piece of imitation wood-grain paper to the surface of a drawing. Nevertheless, his motive, and Picasso's in following him (assuming that Picasso did follow him in this), seems quite apparent by now — so apparent that one wonders why those who write on collage continue to find its origin in nothing more than the Cubists' need for renewed contact with 'reality'.
By the end of 1911 both masters had pretty well turned traditional illusionist paintings inside out. The fictive depths of the picture had been drained to a level very close to the actual paint surface. Shading and even perspective of a sort, in being applied to the depiction of volumetric surfaces as sequences of small facet-planes, had had the effect of tautening instead of hollowing the picture plane. It had become necessary to discriminate more explicitly between the resistant reality of the flat surface and the forms shown upon it in yielding, ideated depth. Otherwise they would become too immediately one with the surface and survive solely as surface pattern. In 1910 Braque had already inserted a very graphic nail with a sharp cast shadow in a picture otherwise devoid of graphic definitions and cast shadows, Still-life with Violin and Palette, in order to interpose a kind of photographic space between the surface and the dimmer, fragile illusoriness of the Cubist space which the still-life itself — shown as a picture within a picture — inhabited. And something similar was obtained by the sculptural delineation of a loop of rope in the upper left margin of the Museum of Modern Art's Man with a Guitar of 1911. In that same year Braque introduced capital letters and numbers stencilled in trompe-l'oeil in paintings whose motifs offered no realistic excuse for their presence. These intrusions, by their self-evident, extraneous and abrupt flatness, stopped the eye at the literal, physical surface of the canvas in the same way that the artist's signature did; here it was no longer a question of interposing a more vivid illusion of depth between surface and Cubist space, but one of specifying the very real flatness of the picture plane so that everything else shown on it would be pushed into illusioned space by force of contrast. The surface was now explicitly instead of implicitly indicated as a tangible but transparent plane.
It was towards the same end that Picasso and Braque began, in 1912, to mix sand____________________