Anamorphosis

Anamorphosis is a distorted projection that requires the viewer to occupy a specific vantage point, use special devices, or both to view a recognizable image. It is used in painting, photography, sculpture and installation, toys, and film special effects. The word is derived from the Greek prefix ana-, meaning "back" or "again", and the word morphe, meaning "shape" or "form". Extreme anamorphosis has been used by artists to disguise caricatures, erotic and scatological scenes, and other furtive images from a casual spectator, while revealing an undistorted image to the knowledgeable viewer. There are two main types of anamorphosis: perspective (oblique) and mirror (catoptric). More complex anamorphoses can be devised using distorted lenses, mirrors, or other optical transformations. An oblique anamorphism forms an affine transformation of the subject. Early examples of perspectival anamorphosis date to the Renaissance of the fifteenth century and largely relate to religious themes. With mirror anamorphosis, a conical or cylindrical mirror is placed on the distorted drawing or painting to reveal an undistorted image. The deformed picture relies on laws regarding angles of incidence of reflection. The length of the flat drawing's curves are reduced when viewed in a curved mirror, such that the distortions resolve into a recognizable picture. Unlike perspective anamorphosis, catoptric images can be viewed from many angles. The technique was originally developed in China during the Ming Dynasty, and the first European manual on mirror anamorphosis was published around 1630 by the mathematician Vaulezard. Channel anamorphosis or tabula scalata has a different image on each side of a corrugated carrier. A straight frontal view shows an unclear mix of the images, while each image can be viewed correctly from a certain angle. The Stone Age cave paintings at Lascaux may make use of anamorphic technique, because the oblique angles of the cave would otherwise result in distorted figures from a viewer's perspective.