How did Masaccio’s use of perspective and consistent light differ from medieval painting?

Masaccio’s approach to painting represented a decisive break from the Middle Ages, during which time pictures were often conceived as worlds governed by arbitrary physical laws. In contrast, Masaccio treated a painting as a window into a continuation of the real world, applying the same consistent laws of space, light, and form that exist in reality.1

His innovations included:

• Consistent Light: Rather than relying solely on line, Masaccio used strongly differentiated areas of light and dark to model figures and shapes. This technique created a convincing illusion of three-dimensional volume, a significant departure from the more decorative or linear styles prevalent in medieval art.12
• Rational Perspective: Masaccio embraced the mathematical system of linear perspective, which uses orthogonals, a horizon line, and a vanishing point to create a realistic illusion of depth on a flat surface. By rendering objects increasingly smaller as they recede toward the vanishing point, he established a clear, controlled space that mirrored the viewer's own experience of reality.13

These advancements allowed Masaccio to create anatomically convincing figures that occupied a rational, unified environment, fundamentally shifting the trajectory of Renaissance art.14