Summary
Highlights
Early 14th-century paintings, like Duccio's, attempted to create realistic spaces, but the architectural elements often didn't cohere logically. This wasn't necessarily a 'problem' for Duccio, but it highlighted a challenge for later Renaissance artists aiming for accurate realism.
In 1420 Florence, Brunelleschi, an architect and engineer, rediscovered linear perspective as a way to accurately sketch ancient Roman buildings. Fifteen years later, Alberti codified this discovery in his book 'On Painting' (1435), explaining the system for artists.
One-point linear perspective, or scientific perspective, consists of three basic elements: a vanishing point (VP), a horizon line (H), and orthogonals. The vanishing point is typically placed in the middle of the painting.
To create a basic interior, rays are drawn from the vanishing point to the bottom line (floorboards). Artists could intuitively do this. The challenge arose when creating horizontal elements like a tiled floor, where the lines needed to get progressively closer as they receded in space to avoid distortion.
Alberti's key insight was to introduce a second point in space, outside the picture plane, at the level of the viewer's eye (the horizon line). By drawing rays from this point to the 'floorboards', and then connecting the intersections, accurate horizontal lines for a tiled floor can be created, creating the illusion of depth.
The goal of linear perspective is to create a convincing 'illusion of reality' on a two-dimensional surface. Alberti famously stated that a painting should be like a window, allowing the viewer to look through to a continuation of their own world.
When placing figures in a perspectival drawing, their eye level should ideally align with the horizon line, regardless of their distance from the viewer. This means the heads of figures are on the same level, while their feet are at different levels, which can be counter-intuitive.
Artists in the Renaissance, like Leonardo da Vinci, used linear perspective not just for realism but also expressively. In 'The Last Supper', the orthogonals converge at the vanishing point, which is precisely at Jesus Christ's head, drawing the viewer's attention to the divine figure.