How do you paint a flat picture that looks like a window onto a deep room? Roman painters had suggested depth by eye, and Giotto by solid figures. In Florence around 1415 to 1420, the architect Filippo Brunelleschi showed a mathematical answer. He painted a small panel of the Baptistery as seen from the cathedral door, drilled a hole in it, and had viewers look through the back at a mirror held in front: the reflected painting lined up with the real building. In 1435 the scholar Leon Battista Alberti wrote down the method in his book On Painting.
- Horizon line: a horizontal line at the viewer's eye level.
- Vanishing point: a point on the horizon where lines running straight away from the viewer seem to meet.
- Orthogonals: those receding lines (floor tiles, the tops of walls, a table edge), all aimed at the vanishing point.
- Objects shrink at a steady rate as they go back, so you can measure how big a far figure should be.
Key idea
Why it works
Looking closely: The Tribute Money. A tax collector, his back to us, demands payment. In the center Christ, among his apostles, points to the lake; at the left Peter kneels there and finds a coin in a fish's mouth; at the right he pays the collector. One picture holds three moments: a continuous narrative. The apostles stand like heavy columns in a circle around Christ, lit from the right, each casting a shadow, and the building's lines run back to Christ's head. Masaccio died at about 27, but this fresco shaped Florentine painting for a century.
Worked example: Find the vanishing point
- Follow the ceiling beams and wall edges inward.
- They meet at Christ's head, at the center of the painting.
- The point that organizes the space is also the focus of the story.
Answer: At Christ's head.
Common mistake