Abstract

In a class on art history, where one works with slides [Diapositiven], it can sometimes happen that a plate, wrongly placed, will yield an image in reverse. Then there is usually the irritated interjection: “Turn it around! The plate is not correct!” but one might well consider why the image cannot be set in reverse and what about its effect changes. That the right hands become the left is in the end irrelevant, but it is in fact the case that even apparently perfect symmetries like those of Raphael’s Sistine Madonna or Holbein’s Darmstadt Madonna do not tolerate such inversion.