Abstract
This paper makes a perspective-analysis of the compositional structure of the Portico, characterized by Sanpaolesi as an 'architettura disegnata' or a painted architecture, rather a full-sized architectural drawing. Principal conclusions of the present study are as follows, [1] The perspective ratio (1 : 1 : 1…) of the structure of the Portico was clarified. The ratio means a mathematical description of the way of disposition or connection at equal distance, more exactly, on a picture plain at a certain distance, of the "element-form", compositional unity or 'standardized form' of the structure in Benevolo's term. [2] The perspective ratio (1 : 1 : 1…) is a quantitative-non-variation rule in the disposition of the "element-form"; the ratio (1 : 1/2 : 1/3…), clarified in a previous analysis of the structure of the Old Sacristy of San Lorenzo, is its quantitative-variation rule, which means a way of its disposition in depth. [3] This set of perspective ratios and a priori determined "element-form" constitute the system of Brunelleschi's design method, which derived all from the famous study on the San Giovanni Baptistery perspective panel prosecuted and demonstrated by this architect to the Florentine citizens in supposedly the years of his designing the Portico and the Old Sacristy.
