Free The Notebooks of Leonardo Da Vinci by Leonardo Da Vinci Page B

second
perspective [= pyramid] results from the first.
    90.
SIMPLE PERSPECTIVE.
    Simple perspective is that which is constructed by art on a vertical
plane which is equally distant from the eye in every part. Complex
perspective is that which is constructed on a ground-plan in which
none of the parts are equally distant from the eye.
    91.
PERSPECTIVE.
    No surface can be seen exactly as it is, if the eye that sees it is
not equally remote from all its edges.
    92.
WHY WHEN AN OBJECT IS PLACED CLOSE TO THE EYE ITS EDGES ARE
INDISTINCT.
    When an object opposite the eye is brought too close to it, its
edges must become too confused to be distinguished; as it happens
with objects close to a light, which cast a large and indistinct
shadow, so is it with an eye which estimates objects opposite to it;
in all cases of linear perspective, the eye acts in the same way as
the light. And the reason is that the eye has one leading line (of
vision) which dilates with distance and embraces with true
discernment large objects at a distance as well as small ones that
are close. But since the eye sends out a multitude of lines which
surround this chief central one and since these which are farthest
from the centre in this cone of lines are less able to discern with
accuracy, it follows that an object brought close to the eye is not
at a due distance, but is too near for the central line to be able
to discern the outlines of the object. So the edges fall within the
lines of weaker discerning power, and these are to the function of
the eye like dogs in the chase which can put up the game but cannot
take it. Thus these cannot take in the objects, but induce the
central line of sight to turn upon them, when they have put them up.
Hence the objects which are seen with these lines of sight have
confused outlines.
    The relative size of objects with regard to their distance from the
eye (93-98).
    93.
PERSPECTIVE.
    Small objects close at hand and large ones at a distance, being seen
within equal angles, will appear of the same size.
    94.
PERSPECTIVE.
    There is no object so large but that at a great distance from the
eye it does not appear smaller than a smaller object near.
    95.
    Among objects of equal size that which is most remote from the eye
will look the smallest. [Footnote: This axiom, sufficiently clear in
itself, is in the original illustrated by a very large diagram,
constructed like that here reproduced under No. 108.
    The same idea is repeated in C. A. I a; I a, stated as follows: Infra le cose d'equal grandeza quella si dimostra di minor figura
che sara pi� distante dall' ochio .—]
    96.
    Why an object is less distinct when brought near to the eye, and why
with spectacles, or without the naked eye sees badly either close or
far off [as the case may be].
    97.
PERSPECTIVE.
    Among objects of equal size, that which is most remote from the eye
will look the smallest.
    98.
PERSPECTIVE.
    No second object can be so much lower than the first as that the eye
will not see it higher than the first, if the eye is above the
second.
PERSPECTIVE.
    And this second object will never be so much higher than the first
as that the eye, being below them, will not see the second as lower
than the first.
PERSPECTIVE.
    If the eye sees a second square through the centre of a smaller one,
that is nearer, the second, larger square will appear to be
surrounded by the smaller one.
PERSPECTIVE—PROPOSITION.
    Objects that are farther off can never be so large but that those in
front, though smaller, will conceal or surround them.
DEFINITION.
    This proposition can be proved by experiment. For if you look
through a small hole there is nothing so large that it cannot be
seen through it and the object so seen appears surrounded and
enclosed by the outline of the sides of the hole. And if you stop it
up, this small stopping will conceal the view of the largest object.
    The apparent size of objects defined by calculation (99-105)
    99.
OF LINEAR PERSPECTIVE.
    Linear Perspective