Textual criticism of drawings in historical/scientific treatise on representation. The Caput in De prospectiva pingendi

The proposed article aims to provide a methodological contribution to reading historical/scientific treatise on representation. In philology, textual criticism is the critical analysis of literary texts aimed at a deep understanding of the text and the author’s intentions. In historical/scientific treatises on representation, the work is composed of two “texts” of equal importance: one is literary, the other graphic. In these cases therefore, textual criticism should be applied to both “texts” at the same time. The case study chosen to investigate the potential of the research method is the first illustrated treatise dedicated to perspective: De Prospectiva Pingendi by Piero della Francesca. While this is a work aimed at painters, the theoretical principles and applications of perspective are also addressed, contributing to a definition of the scientific basis of descriptive geometry. The bibliography is very rich, including essays by C. Winterberg (1899), G. Nicco Fasola (1942), M. Kemp (1994), and K. Andersen (2007). However, it should be noted that graphics that could explain the reasoning behind Piero della Francesca’s drawing are not always included, especially in critical editions. Among the pages of the treatise, proposition 8 in book III holds particular importance for the proposed investigation. Here, Piero constructs the perspective of a human head, which is first positioned straight (frontal position), and then looks upwards (generic position). This proposition represents a major step in that for the first and only time, the author addresses the theme of free forms. To read this proposition critically, it is necessary to refer to a hybrid digital model (polygonal mesh, T-Splines, and NURBS) developed by studying the codices housed in the Palatina Library in Parma and the Municipal Library in Bordeaux. Construction of the digital model allows us to understand both Piero’s refined spatial reasoning and its relative plane rendering in an original reverse path that highlights the scientific nature of the entire treatise and the potential of digital representation as applied to the textual criticism of drawings.