Concept
Depth cue — where it appears
2 essays name this object, across 2 fields. What follows is each of them, and the objects they name alongside it.
A picture with no size–distance signal
In a system with no diminution the drawn size of an object falls at exactly zero pixels per metre, so nothing in the picture says how far away anything is. Depth has to be carried by something else, and what carries it is height on the page — linearly, and without a horizon.
Standing in the wrong place
A picture read from twice the distance it is correct from depicts a scene twice as deep — and not one mark on the paper moves. The error is invisible in the picture, which is why it survives everywhere.
Named alongside it
The objects these essays reach for when they reach for this one.
Picture planeDepth compressionDiminutionDrawing systemFocal lengthForeshorteningHorizonline at infinityOblique projectionParallel projectionProjective reconstructionStation point