The Notebooks of Leonardo Da Vinci — Complete
any distance; and it shows all these objects just as the eye sees
them diminished, without obliging a man to stand in one place rather
than another so long as the plane does not produce a second
foreshortening.
But the second practice is a combination of perspective derived
partly from art and partly from nature and the work done by its
rules is in every portion of it, influenced by natural perspective
and artificial perspective. By natural perspective I mean that the
plane on which this perspective is represented is a flat surface,
and this plane, although it is parallel both in length and height,
is forced to diminish in its remoter parts more than in its nearer
ones. And this is proved by the first of what has been said above,
and its diminution is natural. But artificial perspective, that is
that which is devised by art, does the contrary; for objects equal
in size increase on the plane where it is foreshortened in
proportion as the eye is more natural and nearer to the plane, and
as the part of the plane on which it is figured is farther from the
eye.
And let this plane be _d e_ on which are seen 3 equal circles which
are beyond this plane _d e_, that is the circles _a b c_. Now you
see that the eye _h_ sees on the vertical plane the sections of the
images, largest of those that are farthest and smallest of the
nearest.
108.
Here follows what is wanting in the margin at the foot on the other
side of this page.
Natural perspective acts in a contrary way; for, at greater
distances the object seen appears smaller, and at a smaller distance
the object appears larger. But this said invention requires the
spectator to stand with his eye at a small hole and then, at that
small hole, it will be very plain. But since many (men's) eyes
endeavour at the same time to see one and the same picture produced
by this artifice only one can see clearly the effect of this
perspective and all the others will see confusion. It is well
therefore to avoid such complex perspective and hold to simple
perspective which does not regard planes as foreshortened, but as
much as possible in their proper form. This simple perspective, in
which the plane intersects the pyramids by which the images are
conveyed to the eye at an equal distance from the eye is our
constant experience, from the curved form of the pupil of the eye on
which the pyramids are intersected at an equal distance from the
visual virtue.
[Footnote 24: _la prima di sopra_ i. e. the first of the three
diagrams which, in the original MS., are placed in the margin at the
beginning of this chapter.]
109.
OF A MIXTURE OF NATURAL AND ARTIFICIAL PERSPECTIVE.
This diagram distinguishes natural from artificial perspective. But
before proceeding any farther I will define what is natural and what
is artificial perspective. Natural perspective says that the more
remote of a series of objects of equal size will look the smaller,
and conversely, the nearer will look the larger and the apparent
size will diminish in proportion to the distance. But in artificial
perspective when objects of unequal size are placed at various
distances, the smallest is nearer to the eye than the largest and
the greatest distance looks as though it were the least of all; and
the cause of this is the plane on which the objects are represented;
and which is at unequal distances from the eye throughout its
length. And this diminution of the plane is natural, but the
perspective shown upon it is artificial since it nowhere agrees with
the true diminution of the said plane. Whence it follows, that when
the eye is somewhat removed from the [station point of the]
perspective that it has been gazing at, all the objects represented
look monstrous, and this does not occur in natural perspective,
which has been defined above. Let us say then, that the square _a b
c d_ figured above is foreshortened being seen by the eye situated
in the centre of the side which is in front. But a mixture of
artificial and natural perspective will be seen in this tetragon
called _el main_ [Footnote 20: _el main_ is quite legibly written in
the original; the meaning and derivation of the word are equally
doubtful.], that is to say _e f g h_ which must appear to the eye of
the spectator to be equal to _a b c d_ so long as the eye remains in
its first position between _c_ and _d_. And this will be seen to
have a good effect, because the natural perspective of the plane
will conceal the defects which would [otherwise] seem monstrous.
_III._
_Six books on Light and Shade._
_Linear Perspective cannot be immediately followed by either the_
"prospettiva de' perdimenti" _or the_ "prospettiva de' colori" _or
the aerial perspective; since these branches of the subject
presuppose a knowledge of the principles of Light and Shade. No
apology, therefore, is here needed for placing these immediately
after Linear Perspective._
_We have various plans suggested by Leonardo for the arrangement of
the mass of materials treating of this subject. Among these I have
given the preference to a scheme propounded in No._ III, _because,
in all probability, we have here a final and definite purpose
expressed. Several authors have expressed it as their opinion that
the Paris Manuscript_ C _is a complete and finished treatise on
Light and Shade. Certainly, the Principles of Light and Shade form
by far the larger portion of this MS. which consists of two separate
parts; still, the materials are far from being finally arranged. It
is also evident that he here investigates the subject from the point
of view of the Physicist rather than from that of the Painter._
_The plan of a scheme of arrangement suggested in No._ III _and
adopted by me has been strictly adhered to for the first four Books.
For the three last, however, few materials have come down to us; and
it must be admitted that these three Books would find a far more
appropriate place in a work on Physics than in a treatise on
Painting. For this reason I have collected in Book V all the
chapters on Reflections, and in Book VI I have put together and
arranged all the sections of MS._ C _that belong to the book on
Painting, so far as they relate to Light and Shade, while the
sections of the same MS. which treat of the_ "Prospettiva de'
perdimenti" _have, of course, been excluded from the series on Light
and Shade._
[Footnote III: This text has already been published with some slight
variations in Dozio's pamphlet _Degli scritti e disegni di Leonardo
da Vinci_, Milan 1871, pp. 30--31. Dozio did not transcribe it from
the original MS. which seems to have remained unknown to him, but
from an old copy (MS. H. 227 in the Ambrosian Library).]
GENERAL INTRODUCTION.
Prolegomena.
110.
You must first explain the theory and then the practice. First you
must describe the shadows and lights on opaque objects, and then on
transparent bodies.
Scheme of the books on Light and shade.
111.
INTRODUCTION.
[Having already treated of the nature of shadows and the way in
which they are cast [Footnote 2: _Avendo io tractato._--We may
suppose that he here refers to some particular MS., possibly Paris
C.], I will now consider the places on which they fall; and their
curvature, obliquity, flatness or, in short, any character I may be
able to detect in them.]
Shadow is the obstruction of light. Shadows appear to me to be of
supreme importance in perspective, because, without them opaque and
solid bodies will be ill defined; that which is contained within
their outlines and their boundaries themselves will be
ill-understood unless they are shown against a background of a
different tone from themselves. And therefore in my first
proposition concerning shadow I state that every opaque body is
surrounded and its whole surface enveloped in shadow and light. And
on this proposition I build up the first Book. Besides this, shadows
have in themselves various degrees of darkness, because they are
caused by the absence of a variable amount of the luminous rays; and
these I call Primary shadows because they are the first, and
inseparable from the object to which they belong. And on this I will
found my second Book. From these primary shadows there result
certain shaded rays which are diffused through the atmosphere and
these vary in character according to that of the primary shadows
whence they are derived. I shall therefore call these shadows
Derived shadows because they are produced by other shadows; and the
third Book will treat of these. Again these derived shadows, where
they are intercepted by various objects, produce effects as various
as the places where they are cast and of this I will treat in the
fourth Book. And since all round the derived shadows, where the
derived shadows are intercepted, there is always a space where the
light falls and by reflected dispersion is thrown back towards its
cause, it meets the original shadow and mingles with it and modifies
it somewhat in its nature; and on this I will compose my fifth Book.
Besides this, in the sixth Book I will investigate the many and
various diversities of reflections resulting from these rays which
will modify the original [shadow] by [imparting] some of the various
colours from the different objects whence these reflected rays are
derived. Again, the seventh Book will treat of the various distances
that may exist between the spot where the reflected rays fall and
that where they originate, and the various shades of colour which
they will acquire in falling on opaque bodies.
Different principles and plans of treatment (112--116).
112.
First I will treat of light falling through windows which I will
call Restricted [Light] and then I will treat of light in the open
country, to which I will give the name of diffused Light. Then I
will treat of the light of luminous bodies.
113.
OF PAINTING.
The conditions of shadow and light [as seen] by the eye are 3. Of
these the first is when the eye and the light are on the same side
of the object seen; the 2nd is when the eye is in front of the
object and the light is behind it. The 3rd is when the eye is in
front of the object and the light is on one side, in such a way as
that a line drawn from the object to the eye and one from the object
to the light should form a right angle where they meet.
114.
OF PAINTING.
This is another section: that is, of the nature of a reflection
(from) an object placed between the eye and the light under various
aspects.
115.
OF PAINTING.
As regards all visible objects 3 things must be considered. These
are the position of the eye which sees: that of the object seen
[with regard] to the light, and the position of the light which
illuminates the object, _b_ is the eye, _a_ the object seen, _c_ the
light, _a_ is the eye, _b_ the illuminating body, _c_ is the
illuminated object.
116.
Let _a_ be the light, _b_ the eye, _c_ the object seen by the eye
and in the light. These show, first, the eye between the light and
the body; the 2nd, the light between the eye and the body; the 3rd
the body between the eye and the light, _a_ is the eye, _b_ the
illuminated object, _c_ the light.
117.
OF PAINTING.
OF THE THREE KINDS OF LIGHT THAT ILLUMINATE OPAQUE BODIES.
The first kind of Light which may illuminate opaque bodies is called
Direct light--as that of the sun or any other light from a window or
flame. The second is Diffused [universal] light, such as we see in
cloudy weather or in mist and the like. The 3rd is Subdued light,
that is when the sun is entirely below the horizon, either in the
evening or morning.
118.
OF LIGHT.
The lights which may illuminate opaque bodies are of 4 kinds. These
are: diffused light as that of the atmosphere, within our horizon.