A contribution to the history of representation. The unpublished treatise by Matteo Zaccolini

The unpublished treatise by Matteo Zaccolini, Teatin father, painter and teacher of perspective, was composed in Rome in the first quarter of the seventeenth century and is composed by four books. The fourth book, entitled “The delineation of the shadow produced by opaque rectilinear bodies above the flat surface”, is dedicated to the projection of the shadows in perspective representation and is the most interesting for the history of scientific representation as it collects a vast catalogue of examples in which prismatic bodies project shadows on variously oriented flat surfaces, cylinders, cones and spheres. The projection of shadows produced by extended and multiple light sources and the knowledge of conic curves as planar sections of quadratic surfaces is also addressed. The graphic equipment is rich and characterized by the double draft of each drawing: the first version, drafted only by the shape’s outline, shows all the construction lines; the second version, characterized by the chiaroscuro, hasn’t any construction lines. The in-depth critical analisys of the volume allowed to give Zaccolini back a significant role in the panorama of the history of the science of representation in reference to the study of shadows in the perspective projection.