283.
WHAT PORTION OF A COLOURED SURFACE OUGHT IN REASON TO BE THE MOST INTENSE.
If a is the light, and b illuminated by it in a direct line, c, on which the light cannot fall, is lighted only by reflection from b which, let us say, is red. Hence the light reflected from it, will be affected by the hue of the surface causing it and will tinge the surface c with red. And if c is also red you will see it much more intense than b; and if it were yellow you would see there a colour between yellow and red.
On the use of dark and light colours in painting (284--286).
284.
WHY BEAUTIFUL COLOURS MUST BE IN THE [HIGHEST] LIGHT.
Since we see that the quality of colour is known [only] by means of light, it is to be supposed that where there is most light the
true character of a colour in light will be best seen; and where there is most shadow the colour will be affected by the tone of that. Hence, O Painter! remember to show the true quality of colours in bright lights.
285.
An object represented in white and black will display stronger relief than in any other way; hence I would remind you O Painter! to dress your figures in the lightest colours you can, since, if you put them in dark colours, they will be in too slight relief and inconspicuous from a distance. And the reason is that the shadows of all objects are dark. And if you make a dress dark there is little variety in the lights and shadows, while in light colours there are many grades.
286.
OF PAINTING.
Colours seen in shadow will display more or less of their natural brilliancy in proportion as they are in fainter or deeper shadow. But if these same colours are situated in a well-lighted place, they will appear brighter in proportion as the light is more brilliant. THE ADVERSARY.
The variety of colours in shadow must be as great as that of the colours in the objects in that shadow. THE ANSWER.
Colours seen in shadow will display less variety in proportion as the shadows in which they lie are deeper. And evidence of this is
to be had by looking from an open space into the doorways of dark and shadowy churches, where the pictures which are painted in various colours all look of uniform darkness.
Hence at a considerable distance all the shadows of different colours will appear of the same darkness.
It is the light side of an object in light and shade which shows the true colour.
On the colours of the rainbow (287. 288).
287.
Treat of the rainbow in the last book on Painting, but first write the book on colours produced by the mixture of other colours, so
as to be able to prove by those painters' colours how the colours of the rainbow are produced.
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288.
WHETHER THE COLOURS OF THE RAINBOW ARE PRODUCED BY THE SUN.
The colours of the rainbow are not produced by the sun, for they occur in many ways without the sunshine; as may be seen by holding a glass of water up to the eye; when, in the glass--where there are those minute bubbles always seen in coarse glass--each bub-ble, even though the sun does not fall on it, will produce on one side all the colours of the rainbow; as you may see by placing the glass between the day light and your eye in such a way as that it is close to the eye, while on one side the glass admits the [diffused] light of the atmosphere, and on the other side the shadow of the wall on one side of the window; either left or right, it matters not which. Then, by turning the glass round you will see these colours all round the bubbles in the glass &c. And the rest shall be said in its place.
THAT THE EYE HAS NO PART IN PRODUCING THE COLOURS OF THE RAINBOW.
In the experiment just described, the eye would seem to have some share in the colours of the rainbow, since these bubbles in the glass do not display the colours except through the medium of the eye. But, if you place the glass full of water on the window sill, in such a position as that the outer side is exposed to the sun's rays, you will see the same colours produced in the spot of light thrown through the glass and upon the floor, in a dark place, below the window; and as the eye is not here concerned in it, we may evidently, and with certainty pronounce that the eye has no share in producing them.
OF THE COLOURS IN THE FEATHERS OF CERTAIN BIRDS.
There are many birds in various regions of the world on whose feathers we see the most splendid colours produced as they move, as
we see in our own country in the feathers of peacocks or on the necks of ducks or pigeons, &c.
Again, on the surface of antique glass found underground and on the roots of turnips kept for some time at the bottom of wells or other stagnant waters [we see] that each root displays colours similar to those of the real rainbow. They may also be seen when oil has been placed on the top of water and in the solar rays reflected from the surface of a diamond or beryl; again, through the angular facet of a beryl every dark object against a background of the atmosphere or any thing else equally pale-coloured is surrounded by these rainbow colours between the atmosphere and the dark body; and in many other circumstances which I will not mention, as these suffice for my purpose.
VI.
'Prospettiva de' colri' (Perspective of Colour)
and
'Prospettiva aerea' (Aerial Perspective).
Leonardo distinctly separates these branches of his subject, as may be seen in the beginning of No. 295. Attempts have been made to cast doubts on the results which Leonardo arrived at by experiment on the perspective of colour, but not with justice, as may be seen from the original text of section 294.
The question as to the composition of the atmosphere, which is inseparable from a discussion on Aerial Perspective, forms a separate theory which is treated at considerable length. Indeed the author enters into it so fully that we cannot escape the conviction that he must have dwelt with particular pleasure on this part of his subject, and that he attached great importance to giving it a character of general applicability.
General rules (289--291).
289.
The variety of colour in objects cannot be discerned at a great distance, excepting in those parts which are directly lighted up by the solar rays.
290.
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As to the colours of objects: at long distances no difference is perceptible in the parts in shadow.
291.
OF THE VISIBILITY OF COLOURS.
Which colour strikes most? An object at a distance is most conspicuous, when it is lightest, and the darkest is least visible. An exceptional case.
292.
Of the edges [outlines] of shadows. Some have misty and ill defined edges, others distinct ones.
No opaque body can be devoid of light and shade, except it is in a mist, on ground covered with snow, or when snow is falling on
the open country which has no light on it and is surrounded with darkness.
And this occurs [only] in spherical bodies, because in other bodies which have limbs and parts, those sides of limbs which face each
other reflect on each other the accidental [hue and tone] of their surface.
An experiment.
293.
ALL COLOURS ARE AT A DISTANCE UNDISTINGUISHABLE AND UNDISCERNIBLE.
All colours at a distance are undistinguishable in shadow,