A perspective on reality
Linear perspective. The art historians16 tell us that this, known in antiq- uity and lost in the Dark Ages, was rediscovered in the early years of the fifteenth century by the Florentine architect Filippo Brunelleschi. In effect Brunelleschi asked himself the following question: is it possible to make a drawing of a building which looks exactly like the building itself? His answer, in an ingenious experiment with a mirror, was yes, it was.17 With appropriate care a depiction could indeed reproduce the proportions of the object that it represented. The system of lin- ear perspective so derived was developed and formalised by a further Renaissance architect, Leon Battista Alberti in his Della Pittura which appeared in 1435. The art, or the science, he told his readers, is to think of a picture as if it were a window, looking out in the direction of what- ever is to be drawn. Or better, to think of it as an initially transparent screen, through which the external world can be seen.
But how to do this? Alberti makes two moves. The first is to imagine that there are lines of sight, coming from outside the window/screen, and passing through the screen to the eye of the painter. If the painter can mark the point where they pass through the screen on the way to his eye, then he or she will successfully mimic whatever is outside. The lumpy three-dimensional reality beyond the figurative window is thus converted into a two-dimensional representation. The first move, then, imagines a cone of vision starting, or ending, at the eye. Lines of sight beginning or ending in the eye, fan out, through the figurative window to the objects in the world beyond that window.
The second is to invent something that is usually called the vanishing point. The issue here is, how best to preserve the proportions of objects that are out there, in the world, when they are being transformed into a
representation
on
a
two-dimensional
surface.
Alberti
suggests,
in
part,
that
we
imagine
a
second
cone,
another
fan.
But
this
time,
instead
of
converging
in
the
eye
of
the
artist,
it
converges
on
the
other
side
of
the
picture/window,
in
the
middle
of
the
field
of
view,
at
a
distant
point
on
the
horizon,
directly
opposite
the
eye
of
the
artist.
This,
then,
becomes
the
point
at
which
those
edges
of
objects
in
the
real
world
that
are
at
right
angles
to
the
picture/window
tend
to
converge.
To
help
in
painting
the
artist
now
needs
to
draw
this
second
cone,
to
depict
it
on
the
two-
dimensional
surface
of
the
picture/window.
What form does this take? The answer is that it becomes a set of lines radiating out from a single point on the surface. This becomes the vanishing point. And the location of the vanishing point is fixed because it is where the line joining the centre of the two cones that have been created – the one converging on the distant vanishing point out there in the world, and the other, in here, in the eye of the artist – passes through the surface of the picture/window.18
This theorising is only a small part of the story. The conventions of linear perspective were being developed in the last years of the fourteenth century among artists in Italy. Art historians such as Norman Bryson (1983) show that it indeed took several generations for the new techniques to become established in the repertoire of the Renaissance artists.19 This is partly because there were other powerful representational traditions available, for instance to do with the all-seeing eye of God, and symbolisms attached to various depicted features of nature or the gesture. Nevertheless it led to such powerful representations as Raphael’s Marriage of the Virgin.20