MAIGNAN, Emanuele
Perspective Horlogia sive De Horographia Gnominica tum theoretica . . .
Rome: Filippo Rossi, 1648
First Edition.
Folio. (14) ff., 705, (1) pp, 45 full-page engraved plates, 1 folding table, engraved frontispiece.
Contemporary blindstamped pigskin, two brass clasps.
In addition to its profound influence on the development of western pictorial art, geometrical perspective addressed a fundamental practical problem - the design of sundials. Calculating the projection of the shadow of a gnomen (the vertical bar of a sundial) cast by the sun onto a background surface is a basic problem in projective geometry that becomes especially complex if the surface is curved. While nominally on the subject of sundials, Emanuele Maignan's Perspectiva Horologia is is a comprehensive treatise that addresses the fundamental mathematics of projective geometry, perspective, and optics, and even includes a detailed section on the design and cutting of optical lenses. In addition to conventional perspective the book discusses anamorphosis - i.e., the perspective from extreme and unorthodox viewpoints. This makes Maignan's book a companion to Niceron's Perspective curieuse, and in fact the two books contain figures illustrating a pair of anamorphic murals that the two authors painted on opposite walls of a cloister gallery in Rome.
The development of perspective in the fifteenth century appeared to force upon the maker and viewer of a picture a single "correct" point of view - namely the unique viewing position from which the picture was most realistic. The geometric rules of perspective were anchored to the position of this viewpoint. This authoritarian quality of the picture was a move away from earlier, medieval pictures that combined pictorial elements from a variety of perspectives, distances, and scales according to their symbolic relationships and allegorical significance. A fixed single-point perspective also differentiated western European renaissance pictures - which were devised as windows onto a scene - from Chinese paintings that attempted to capture the viewer's experience from within the scene.
The strict single point of view in renaissance paintings was subverted by, among others, Hans Holbein, who introduced multiple perspectives into a single picture, most notably in The Ambassadors, where the principal part of the picture is constructed from the conventional face-on perspective but one element - the anamorphic skull in the foreground - occupies a distinct visual space that is completely decoupled from the rest of the picture. One sees two different, equally realistic images depending on one's viewing position. The two images are fully differentiated, without any smooth segue from the one visual construct to the other, as one might obtain by walking past or around the scene in three dimensions.
The use of anamorphosis in renaissance and baroque painting can be seen to presage the experimentation with variable and composite viewpoints in cubist pictures of the early twentieth century. Anamorphic imagery also fit with seventeenth century philosophical speculations that many secrets of nature were displayed "in plain sight" but could be clearly seen only if the correct viewpoint could be found. This was related in turn to cabbalistic-type thinking that suggested that fundamental truths were encrypted in biblical passages, stellar constellation patterns, and other literal or visual "texts", waiting to be properly recognized and decoded. This mode of thought raised cryptographic and steganographic techniques (see Selenus' Cryptomenytices) to a level of interest far above mere secret messages - to wit, to the level that nature herself employed these techniques to conceal important characteristics of physical phenomena.
Frontispiece from Maignan, Perspectiva horlogia, Rome 1648.
Perspective projections onto a curved ceiling (from Maignan, Perspectiva)