Alberti's Perspective Construction

5. The location of the eye in Masaccio's Trinity

Masaccio's fresco of The Trinity was executed in the church of Santa Maria Novella, in Florence, in 1426. It thus predates by several years Alberti's description of the pavement construction. The occurrence of this construction in the design of the barrel vault that encloses the fictional recess in the wall behind the picture plane points to Masaccio's friend Brunelleschi as the true originator of the process. An earmark of the construction is the possibility of running it backwards; we carry this out on Masaccio's masterpiece as follows. (The image of The Trinity is taken with permission from Mark Harden's Artchive where the unmarked image may be admired.)

Masaccio, The Trinity, Santa Maria Novella, Florence (detail).

The superimposed blue lines follow the ``horizontal'' ribs of the vaulting and converge at the vanishing point lower in the fresco. This puts the horizon line approximately 174cm above the bottom of the fresco, which measures 667cm high and 317cm wide. The vault is cylindrical but the squares down the central rib are close enough to horizontal for the diagonals to be tested. They all meet the horizon line near a point about 770cm from the vanishing point. The backwards construction then places the ideal viewpoint at 174cm (about 5 feet 8 inches) above the bottom of the fresco (which is at the floor) and 770cm (25 feet 3 inches) away from the work. Click here for an image of the complete construction.