Visual Plane
every picture states the point it is correct from
Concept

Catoptric — where it appears

2 essays name this object, across one field. What follows is each of them, and the objects they name alongside it.
eye, 74° offgrey: the word before the projectionblack: the same word, projected

Anamorphosis is only a viewpoint

A smear on a wall that resolves into a skull when the viewer stands in one particular place off to the side. It is not a trick added to perspective — it is perspective, with the centre of projection put somewhere nobody would naturally stand, and it is the clearest demonstration there is that every picture has such a point.

viewing · anamorph the sheet, seen from abovemirrorthe eye, 2.4 radii upwhat stands up in the mirrorthe light path reverses to the eye to 1e-15scale varies 7.2× across the design

The cylindrical mirror unbends it

Put a mirrored cylinder in the middle of the sheet and the light path from the eye to the paper bends once. The map that results is not a homography and not a projection in the plane sense at all — it varies its scale by a factor of seven across the design, which is why the smear is unreadable and why the mirror can put it back.

viewing · anamorph

Named alongside it

The objects these essays reach for when they reach for this one.

AnamorphosisArea scaleAzimuthCatoptric anamorphosisCylindrical mirrorHomographyLight pathOblique projectionRectificationReflection

All concepts