The Theory and Practice of Perspective | Page 8

lively and intelligent and
appear to be executed with ease, which shows their authors to be
complete masters of their craft.
The same may be said of the Chinese, although their perspective is
more decorative than true, and whilst their taste is exquisite their whole
art is much more conventional and traditional, and does not remind us
of nature like that of the Japanese.
We may see defects in the perspective of the ancients, in the mediaeval

painters, in the Japanese and Chinese, but are we always right ourselves?
Even in celebrated pictures by old and modern masters there are
occasionally errors that might easily have been avoided, if a ready
means of settling the difficulty were at hand. We should endeavour
then to make this study as simple, as easy, and as complete as possible,
to show clear evidence of its correctness (according to its conditions),
and at the same time to serve as a guide on any and all occasions that
we may require it.
To illustrate what is perspective, and as an experiment that any one can
make, whether artist or not, let us stand at a window that looks out on
to a courtyard or a street or a garden, &c., and trace with a paint-brush
charged with Indian ink or water-colour the outline of whatever view
there happens to be outside, being careful to keep the eye always in the
same place by means of a rest; when this is dry, place a piece of
drawing-paper over it and trace through with a pencil. Now we will rub
out the tracing on the glass, which is sure to be rather clumsy, and,
fixing our paper down on a board, proceed to draw the scene before us,
using the main lines of our tracing as our guiding lines.
If we take pains over our work, we shall find that, without troubling
ourselves much about rules, we have produced a perfect perspective of
perhaps a very difficult subject. After practising for some little time in
this way we shall get accustomed to what are called perspective
deformations, and soon be able to dispense with the glass and the
tracing altogether and to sketch straight from nature, taking little note
of perspective beyond fixing the point of sight and the horizontal-line;
in fact, doing what every artist does when he goes out sketching.
[Illustration: Fig. 6. This is a much reduced reproduction of a drawing
made on my studio window in this way some twenty years ago, when
the builder started covering the fields at the back with rows and rows of
houses.]

THE THEORY OF PERSPECTIVE

DEFINITIONS
I
Fig. 7. In this figure, AKB represents the picture or transparent vertical
plane through which the objects to be represented can be seen, or on
which they can be traced, such as the cube C.
[Illustration: Fig. 7.]
The line HD is the +Horizontal-line+ or +Horizon+, the chief line in
perspective, as upon it are placed the principal points to which our
perspective lines are drawn. First, the +Point of Sight+ and next D, the
+Point of Distance+. The chief vanishing points and measuring points
are also placed on this line.
Another important line is AB, the +Base+ or +Ground line+, as it is on
this that we measure the width of any object to be represented, such as
ef, the base of the square efgh, on which the cube C is raised. E is the
position of the eye of the spectator, being drawn in perspective, and is
called the +Station-point+.
Note that the perspective of the board, and the line SE, is not the same
as that of the cube in the picture AKB, and also that so much of the
board which is behind the picture plane partially represents the
+Perspective-plane+, supposed to be perfectly level and to extend from
the base line to the horizon. Of this we shall speak further on. In nature
it is not really level, but partakes in extended views of the rotundity of
the earth, though in small areas such as ponds the roundness is
infinitesimal.
[Illustration: Fig. 8.]
Fig. 8. This is a side view of the previous figure, the picture plane K
being represented edgeways, and the line SE its full length. It also
shows the position of the eye in front of the point of sight S. The
horizontal-line HD and the base or ground-line AB are represented as
receding from us, and in that case are called vanishing lines, a not quite

satisfactory term.
It is to be noted that the cube C is placed close to the transparent
picture plane, indeed touches it, and that the square fj faces the
spectator E, and although here drawn in perspective it appears to him as
in the other figure.