Les Perspecteurs Plate 2

Abraham Bosse site

Bosse illustrates in this plate what Desargues calls the "radiation of sight" and Alberti the "visual pyramid". The visual rays are materialized by nets attached to the corners of a tile. They assemble in the eye, the theoretical summit of the pyramid. It is therefore a question of setting up the foundations of the linear monocular perspective.

Bosse envisions the following visual dynamic: "Holding the assembly of these threads to your eye in this way, look at this bcdf tile, at the same time, and you will see the corners to the right and along these threads, as if each of those wedges came along one of those threads to your eye or as if your eye saw those wedges through those threads, going from it to them. "

Thus, the observed point runs along the net to the eye to inform it of its position. Later, Bosse will take up the same idea by imagining that the touches, tints or colors of the subject flow along the visual rays to inform the eye of the color of each of the points of the subject. Note that it is possible that the light goes from the eye to the corners of the square bcdf. The direction of light propagation is a debate which is not yet decided by the scientific community of the time, but Bosse, in later writings, will indicate his rational preference for a propagation of light from objects towards the eye.

Bosse also shows in this plate that the position of the eye in relation to the observed square is an essential parameter for the representation of this square. Depending on whether the observer is standing, seated or perched on steps, he does not have the same vision.

This very famous print, which is sometimes called Les Perspecteurs , undoubtedly owes its success to the singular alliance of a refined geometric decoration and characters in refined costumes who engage in a very strange activity. In terms of linear perspective or aerial perspective, it bears witness to Bosse's know-how.

Translation from French care of Google Translate. I suspect Kim H. Veltman would be unimpressed by the translation.