How did collage change the idea of a painting as an illusion?

The development of collage by Georges Braque and Pablo Picasso during the Synthetic Cubism phase fundamentally challenged the traditional role of painting as an illusionistic window into a depicted scene.12

By incorporating "found" materials—such as newspapers, tobacco wrappers, and other scraps—directly onto the canvas, these artists introduced real, three-dimensional textures into the composition. This technique emphasized the flat, two-dimensional nature of the picture plane rather than attempting to mimic depth or imitate nature through traditional perspective, modeling, or chiaroscuro.23

Ultimately, collage forced a shift in the viewer's perception by juxtaposing painted areas with actual physical objects. This contrast highlighted the differences in texture and surface, effectively posing a philosophical question regarding the distinction between reality and artistic illusion.2