What innovative technique was developed in the Renaissance to create depth in artwork?

The technique that was innovatively developed during the Renaissance to create depth in artwork is linear perspective. This method revolutionized the way space was represented in two-dimensional art by allowing artists to create the illusion of depth on a flat surface. Linear perspective relies on the use of vanishing points and horizon lines, enabling objects to appear smaller as they recede into the distance, thus mimicking how the human eye perceives space.

Historically, artists like Filippo Brunelleschi and later Leonardo da Vinci and Raphael employed linear perspective to enhance realism in their paintings. This approach not only provided a mathematical framework but also transformed the viewer's experience, drawing the eye into the depth of the scene.

Other options, though significant in their own right, do not specifically address the innovative technique for creating depth. Collage involves assembling various materials rather than focusing on depth perception. Fresco painting is a technique for mural painting but does not by itself create depth. Mixed media refers to the use of multiple artistic mediums but does not inherently create spatial relationships in design. Linear perspective remains a cornerstone of Renaissance art, demonstrating its fundamental impact on artistic practices that followed.