Schulers Books Online
books - games - software - wallpaper - everything
- Notebooks of Leonardo Da Vinci - 40/159 -
OF THE SHADOWS OF A LEAF.
Sometimes a leaf has three accidents [of light] that is: shade, lustre [reflected light] and transparency [transmitted light]. Thus, if the light were at _n_ as regards the leaf _s_, and the eye at _m_, it would see _a_ in full light, _b_ in shadow and _c_ transparent.
A leaf with a concave surface seen from the under side and up-side-down will sometimes show itself as half in shade, and half transparent. Thus, if _o p_ is the leaf and the light _m_ and the eye _n_, this will see _o_ in shadow because the light does not fall upon it between equal angles, neither on the upper nor the under side, and _p_ is lighted on the upper side and the light is transmitted to its under side. [Footnote: See Pl. XXVIII, No. 2, the upper sketch on the page. In the original they are drawn in red chalk.]
Although those leaves which have a polished surface are to a great extent of the same colour on the right side and on the reverse, it may happen that the side which is turned towards the atmosphere will have something of the colour of the atmosphere; and it will seem to have more of this colour of the atmosphere in proportion as the eye is nearer to it and sees it more foreshortened. And, without exception the shadows show as darker on the upper side than on the lower, from the contrast offered by the high lights which limit the shadows.
The under side of the leaf, although its colour may be in itself the same as that of the upper side, shows a still finer colour--a colour that is green verging on yellow--and this happens when the leaf is placed between
the eye and the light which falls upon it from the opposite side.
And its shadows are in the same positions as those were of the opposite side. Therefore, O Painter! when you do trees close at hand, remember that if the eye is almost under the tree you will see its leaves [some] on the upper and [some] on the under side, and the upper side will be bluer in proportion as they are seen more foreshortened, and the same leaf sometimes shows part of the right side and part of the under side, whence you must make it of two colours.
Of the transparency of leaves (427-429).
The shadows in transparent leaves seen from the under side are the same shadows as there are on the right side of this leaf, they will show through to the underside together with lights, but the lustre [reflected light] can never show through.
When one green has another [green] behind it, the lustre on the leaves and their transparent [lights] show more strongly than in those which are [seen] against the brightness of the atmosphere.
And if the sun illuminates the leaves without their coming between it and the eye and without the eye facing the sun, then the reflected lights and the transparent lights are very strong.
It is very effective to show some branches which are low down and dark and so set off the illuminated greens which are at some distance from the dark greens seen below. That part is darkest which is nearest to the eye or which is farthest from the luminous atmosphere.
Never paint leaves transparent to the sun, because they are confused; and this is because on the transparency of one leaf will be seen the shadow of another leaf which is above it. This shadow has a distinct outline and a certain depth of shade and sometimes is [as much as] half or a third of the leaf which is shaded; and consequently such an arrangement is very confused and the imitation of it should be avoided.
The light shines least through a leaf when it falls upon it at an acute angle.
The gradations of shade and colour in leaves (430-434).
The shadows of plants are never black, for where the atmosphere penetrates there can never be utter darkness.
If the light comes from _m_ and the eye is at _n_ the eye will see the colour of the leaves _a b_ all affected by the colour of _m_ --that is of the atmosphere; and _b c_ will be seen from the under side as transparent, with a beautiful green colour verging on yellow.
If _m_ is the luminous body lighting up the leaf _s_ all the eyes that see the under side of this leaf will see it of a beautiful light green, being transparent.
In very many cases the positions of the leaves will be without shadow [or in full light], and their under side will be transparent and the right side lustrous [reflecting light].
The willow and other similar trees, which have their boughs lopped every 3 or 4 years, put forth very straight branches, and their shadow is about the middle where these boughs spring; and towards the extreme ends they cast but little shade from having small leaves and few and slender branches. Hence the boughs which rise towards the sky will have but little shade and little relief; and the branches which are at an angle from the horizon, downwards, spring from the dark part of the shadow and grow thinner by degrees up to their ends, and these will be in strong relief, being in gradations of light against a background of shadow.
That tree will have the least shadow which has the fewest branches and few leaves.
OF DARK LEAVES IN FRONT OF TRANSPARENT ONES.
When the leaves are interposed between the light and the eye, then that which is nearest to the eye will be the darkest, and the most distant will be the lightest, not being seen against the atmosphere; and this is seen in the leaves which are away from the centre of the tree, that is towards the light.
[Footnote: See Pl. XXVIII, No. 2, the lower sketch.]
OF THE LIGHTS ON DARK LEAVES.
The lights on such leaves which are darkest, will be most near to the colour of the atmosphere that is reflected in them. And the cause of this is that the light on the illuminated portion mingles with the dark hue to compose a blue colour; and this light is produced by the blueness of the atmosphere which is reflected in the smooth surface of these leaves and adds to the blue hue which this light usually produces when it falls on dark objects.
OF THE LIGHTS ON LEAVES OF A YELLOWISH GREEN.
But leaves of a green verging on yellow when they reflect the atmosphere do not produce a reflection verging on blue, inasmuch as every thing which appears in a mirror takes some colour from that mirror, hence the blue of the atmosphere being reflected in the yellow of the leaf appears green, because blue and yellow mixed together make a very fine green colour, therefore the lustre of light leaves verging on yellow will be greenish yellow.
A classification of trees according to their colours.
The trees in a landscape are of various kinds of green, inasmuch as some verge towards blackness, as firs, pines, cypresses, laurels, box and the like. Some tend to yellow such as walnuts, and pears, vines and verdure. Some are both yellowish and dark as chesnuts, holm-oak. Some turn red in autumn as the service-tree, pomegranate, vine, and cherry; and some are whitish as the willow, olive, reeds and the like. Trees are of various forms ...
The proportions of light and shade in trees (436-440).
OF A GENERALLY DISTRIBUTED LIGHT AS LIGHTING UP TREES.
That part of the trees will be seen to lie in the least dark shadow which is farthest from the earth.
To prove it let _a p_ be the tree, _n b c_ the illuminated hemisphere [the sky], the under portion of the tree faces the earth _p c_, that is on the side _o_, and it faces a small part of the hemisphere at _c d_. But the highest part of the convexity a faces the greatest part of the hemisphere, that is _b c_. For this reason--and because it does not face the darkness of the earth--it is in fuller light. But if the tree has dense foliage, as the laurel, arbutus, box or holm oak, it will be different; because, although _a_ does not face the earth, it faces the dark [green] of the leaves cut up by many shadows, and this darkness is reflected onto the under sides of the leaves immediately above. Thus these trees have their darkest shadows nearest to the middle of the tree.
Previous Page Next Page
1 10 20 30 35 36 37 38 39 40 41 42 43 44 45 50 60 70 80 90 100 110 120 130 140 150 159
Schulers Books Online
books - games - software - wallpaper - everything