Theory and Practice in the Implementation of Illusionistic Ceiling Painting at Palazzo Moroni in Bergamo

The construction of Palazzo Moroni was commissioned by Francesco in the occasion of his marriage with Lucrezia Roncalli in 1631. The work lasted thirty years, from 1636 to 1666, and was executed by the master Battista della Giovanna. In 1649, Moroni entrusted to the painter Giacomo Barbelli from Crema (1604-1656) the decoration of some rooms. This is evidenced in the inscription written in the corners of the Gerusalemme Liberata hall: IO.s JACO.s BARBERI.s CREMEN.s INVEN.r PINGEB.t ANNO MDCLII. On the first floor of the building, you will find some amazing illusionistic artifices that impress with their high scenic quality. The illusions show architectural scenes that are able to expand the real space and to open trompe l'oeil ceilings using decorative elements. These examples of excellent workmanship are so specific that deserve to be studied in a national PRIN research on the perspective issues. So, what is the hidden system used by these painters called "quadraturisti"? This work reveals, between hypothesis and validations, the operating stratagems to acquire and describe these works and the perspective reasoning used by the artist to give the illusion of having the sky in a room. Varied technical equipment has been tested to perform the survey. The 3D laser distancemeter measurements have been "dressed" with digital photographs edited with a software that calculates the intersection of optical lines from each photo and projected in three-dimensional space the generated points. The collected data allowed reconstructing the architectural structures with accuracy. The analysis of the digital model has revealed that the unit of measure used was the Bergamasco Foot (0.437767 m). The Gerusalemme Liberata hall measures 32x17 feet. The Golden Age hall measures 16x16 feet. The stairwell measures 34x12,5 feet. The investigation on the ceiling perspective identifies in the first room four vanishing points instead that one. The comparison with the figure 100 in Andrea Pozzo’s Treaty about the “modo di far la graticola nelle volte” (way to do the grids for painted vaults), has led to the hipotesys that Barbelli uses the same method. Pozzo explains that for flat artworks two grids are enough: one on the drawing, the other in the entire work. However, Pozzo himself criticizes the multiple vanishing points solution in a response notice to a raised objection. He states that "not everyone agrees that in a great perspective you give just one point to the whole work" and he replies that to fully enjoy and have an optimal view of the whole work, it is more advisable to have a single point of view. Otherwise, you should look at the drawing from different points in the room, to perceive the whole work. The research’s goal is the geometric analysis and the restitution of the represented architecture. The purpose is to understand the practice for the construction of these kinds of architectonical paintings called “quadrature” and to highlight the peculiarities of the school established in Ducato di Milano. Padre Pozzo himself studied here, before he left the city in order to definitively settle in Rome (1681). The research analyzes a series of similar perspectives, with the aim to identify the elements that explain the theoretical training of Pozzo and his master