Droste effect

The Droste effect is a specific kind of recursive portrait, one that in heraldry is termed mise en abyme. An image exhibiting the Droste effect depicts a minor version of itself in a place where a similar picture would realistically be expected to appear. In this smaller version then depicts an even smaller version of itself in the same place, and so on. Only in assumption could this go on forever; practically, it continues only as long as the resolution of the picture allows, which is moderately short, since each iteration geometrically reduces the picture's size. It is a visual example of a strange loop, a self-referential system of instancing which is the keystone of fractal geometry.

The effect is named after the image on the tins and boxes of Droste cocoa powder, one of the main Dutch brands, which displayed a nurse shipping a serving tray with a cup of hot chocolate and a box with the same image. This image, introduced in 1904 and maintained for decades with small variations, became a household notion. Seemingly, poet and columnist Nico Scheepmaker introduced wider usage of the term in the late 1970s.

The Droste effect is not a new idea. It was for example used by Giotto di Bondone in 1320, in his Stefaneschi Triptych. The polyptych altarpiece portrays in its center panel Cardinal Giacomo Gaetani Stefaneschi contribution the triptych itself to St. Peter. There are also several examples from medieval times of books featuring images containing the book itself or window panels in churches depicting minute copies of the window panel itself.