The Notebooks of Leonardo Da Vinci — Complete
the. reason of this is that it is close to them [Footnote 6: It is
quite inconceivable to me why M. RAVAISSON, in a note to his French
translation of this simple passage should have remarked: _Il est
clair que c'est par erreur que Leonard a ècrit_ per esser visino _au
lieu de_ per non esser visino. (See his printed ed. of MS. A. p.
38.)]; but if these spaces are marked on the vertical plane _n o_
the space _o v_ will be seen at _o r_, and in the same way the space
_v x_ will appear at _r q_. And if you carry this out in any place
where you can walk round, it will look out of proportion by reason
of the great difference in the spaces _o r_ and _r q_. And this
proceeds from the eye being so much below [near] the plane that the
plane is foreshortened. Hence, if you wanted to carry it out, you
would have [to arrange] to see the perspective through a single hole
which must be at the point _m_, or else you must go to a distance of
at least 3 times the height of the object you see. The plane _o p_
being always equally remote from the eye will reproduce the objects
in a satisfactory way, so that they may be seen from place to place.
87.
How every large mass sends forth its images, which may diminish
through infinity.
The images of any large mass being infinitely divisible may be
infinitely diminished.
88.
Objects of equal size, situated in various places, will be seen by
different pyramids which will each be smaller in proportion as the
object is farther off.
89.
Perspective, in dealing with distances, makes use of two opposite
pyramids, one of which has its apex in the eye and the base as
distant as the horizon. The other has the base towards the eye and
the apex on the horizon. Now, the first includes the [visible]
universe, embracing all the mass of the objects that lie in front of
the eye; as it might be a vast landscape seen through a very small
opening; for the more remote the objects are from the eye, the
greater number can be seen through the opening, and thus the pyramid
is constructed with the base on the horizon and the apex in the eye,
as has been said. The second pyramid is extended to a spot which is
smaller in proportion as it is farther from the eye; and this 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 più 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 deals with the action of the lines of sight, in
proving by measurement how much smaller is a second object than the
first, and how much the third is smaller than the second; and so on
by degrees to the end of things visible. I find by experience that
if a second object is as far beyond the first as the first is from
the eye, although they are of the same size, the second will seem
half the size of the first and if the third object is of the same
size as the 2nd, and the 3rd is as far beyond the second as the 2nd
from the first, it will appear of half the size of the second; and
so on by degrees, at equal distances, the next farthest will be half
the size of the former object. So long as the space does not exceed
the length of 20 braccia. But, beyond 20 braccia figures of equal
size will lose 2/4 and at 40 braccia they will lose 9/10, and 19/20
at 60 braccia, and so on diminishing by degrees. This is if the
picture plane is distant from you twice your own height. If it is
only as far off as your own height, there will be a great difference
between the first braccia and the second.
[Footnote: This chapter is included in DUFRESNE'S and MANZI'S
editions of the Treatise on Painting. H. LUDWIG, in his commentary,
calls this chapter "_eines der wichtigsten im ganzen Tractat_", but
at the same time he asserts that its substance has been so
completely disfigured in the best MS. copies that we ought not to
regard Leonardo as responsible for it. However, in the case of this
chapter, the old MS. copies agree with the original as it is
reproduced above. From the chapters given later in this edition,
which were written at a subsequent date, it would appear that
Leonardo corrected himself on these points.]
100.
OF THE DIMINUTION OF OBJECTS AT VARIOUS DISTANCES.
A second object as far distant from the first as the first is from
the eye will appear half the size of the first, though they be of
the same size really.
OF THE DEGREES OF DIMINUTION.
If you place the vertical plane at one braccio from the eye, the
first object, being at a distance of 4 braccia from your eye will
diminish to 3/4 of its height at that plane; and if it is 8 braccia
from the eye, to 7/8; and if it is 16 braccia off, it will diminish
to 15/16 of its height and so on by degrees, as the space doubles
the diminution will double.
101.
Begin from the line _m f_ with the eye below; then go up and do the
same with the line _n f_, then with the eye above and close to the 2
gauges on the ground look at _m n_; then as _c m_ is to _m n_ so
will _n m_ be to _n s_.
If _a n_ goes 3 times into _f b, m p_ will do the same into _p g_.
Then go backwards so far as that _c d_ goes twice into _a n_ and _p
g_ will be equal to _g h_. And _m p_ will go into _h p_ as often as
_d c_ into _o p_.
[Footnote: The first three lines are unfortunately very obscure.]
102.
I GIVE THE DEGREES OF THE OBJECTS SEEN BY THE EYE AS THE MUSICIAN
DOES THE NOTES HEARD BY THE EAR.
Although the objects seen by the eye do, in fact, touch each other
as they recede, I will nevertheless found my rule on spaces of 20
braccia each; as a musician does with notes, which, though they can
be carried on one into the next, he divides into degrees from note
to note calling them 1st, 2nd, 3rd, 4th, 5th; and has affixed a name
to each degree in raising or lowering the voice.
103.
PERSPECTIVE.
Let _f_ be the level and distance of the eye; and _a_ the vertical
plane, as high as a man; let _e_ be a man, then I say that on the
plane this will be the distance from the plane to the 2nd man.
104.
The differences in the diminution of objects of equal size in
consequence of their various remoteness from the eye will bear among
themselves the same proportions as those of the spaces between the
eye and the different objects.
Find out how much a man diminishes at a certain distance and what
its length is; and then at twice that distance and at 3 times, and
so make your general rule.
105.
The eye cannot judge where an object high up ought to descend.
106.
PERSPECTIVE.
If two similar and equal objects are placed one beyond the other at
a given distance the difference in their size will appear greater in
proportion as they are nearer to the eye that sees them. And
conversely there will seem to be less difference in their size in
proportion as they are remote from the eve.
This is proved by the proportions of their distances among
themselves; for, if the first of these two objects were as far from
the eye, as the 2nd from the first this would be called the second
proportion: since, if the first is at 1 braccia from the eye and the
2nd at two braccia, two being twice as much as one, the first object
will look twice as large as the second. But if you place the first
at a hundred braccia from you and the second at a hundred and one,
you will find that the first is only so much larger than the second
as 100 is less than 101; and the converse is equally true. And
again, the same thing is proved by the 4th of this book which shows
that among objects that are equal, there is the same proportion in
the diminution of the size as in the increase in the distance from
the eye of the spectator.
On natural perspective (107--109).
107.
OF EQUAL OBJECTS THE MOST REMOTE LOOK THE SMALLEST.
The practice of perspective may be divided into ... parts [Footnote
4: _in_ ... _parte_. The space for the number is left blank in the
original.], of which the first treats of objects seen by the eye at