
MIRRORS AND REFLECTIONS
"When you wish to see whether your whole picture accords with what you have portrayed from nature take a mirror and reflect the actual object in it. Compare what is reflected with your painting and carefully consider whether both likenesses of the subject correspond, particularly in regard to the mirror."
-Leonardo da Vinci
That the mirror was the mother of Renaissance perspective is a theme taken up by Samuel Edgerton in his The Renaissance Rediscovery of Linear Perspective. He carefully traces the various converging sets of ideas from Greek and Arabic philosophy through medieval optics, geometry and cartography which led to the fateful moment in the Piazza del Duomo in Florence in 1425 when Brunelleschi made his major discovery of the laws of perspective. Mirrors had been standard in artists' studios for several hundred years, for example Giotto had painted "with the aid of mirrors." Yet Brunelleschi's extraordinary breakthrough is the culminating moment. Without what Edgerton calculates to be a twelve-inch-square flat mirror, the most important single change in the representation of nature by artistic means in the last thousand years could not, Edgerton argues, have occurred.
From Alan Macfarlane and Gerry Martin, Glass: A World History (press.uchicago.edu)