Landscapes have their most beautiful blue when, in fair weather, the sun is at midday, more than at any other time of day, because the air is cleared of moisture; and looking in that direction you see the trees beautiful toward their outer parts and the shadows toward the middle dark; and over long distances the air that interposes between you and them becomes more beautiful when behind it is something darker, and therefore the blue is most beautiful.

Things seen from the side on which the sun illuminates them will not show you their shadows. But if you are lower than the sun, you will see what was not seen by the sun, and that will be all shadowed.

The leaves of trees that interpose between you and the sun are of five principal colours: namely, a most beautiful glossy green, and the mirroring of the air that illuminates that which cannot be seen by the sun; and the shadowed ones that see only the ground; and the darkest, which are surrounded by nothing but darkness ...

Much more beautiful are the trees in the countryside that stand between the sun and you than those between which and the sun you stand; and this happens because those toward the sun show, toward their edges, their transparent leaves, while what is not transparent, that is on the edges, is glossy: it is true that the shadows are dark, because nothing occupies them.

The trees between which and the sun you place yourself will show themselves only in their light and natural colour, which in itself is not very excessive; and besides this, some highlights, which, not being against a field too different from their brightness, will be of little distinctness; and if you are lower than they, they may still show you those parts the sun did not see, which will be shadowed.

On the wind.

But if you are on the side from which the wind blows, you will see the trees much brighter than you would from other directions; and this happens because the wind uncovers the undersides of the leaves, which in all trees are much whiter than their upper side; and above all they will be brightest if the wind draws from that region where the sun is, upon which you have turned your back.

All trees seen toward the sun are dark toward the middle; which darkness will be of the shape of their tree, when it is separated from the others.

The derivative shadows of trees seen from the sun are as dark as that of the middle of the tree.

The derivative shadow of trees will never be of lesser amount than the amount of the tree itself; but it will be so much the greater as the site where it is cut is more oblique toward the centre of the world.

That shadow will be narrower toward the middle of the tree whose branching is sparser.

Every branch has the middle of the shadow of any branch, and consequently of its whole tree.

The shape of any shadow of a branch or tree will be clothed with a luminous part on that side from which the light comes; which illumination will be of the shape of the shadows, and this holds for the space of a mile on the side where the sun is.

If it happens that some cloud shadows some part of the hills, its trees change less than their spaces or plains; because the trees on the hills are denser in branches, since they put forth less each year than those on the plains; hence, both by being dark by nature and by being full of shadows, the shadows of clouds cannot darken them further, while the plains that lie between the trees, having lost no shadow, strongly change in their brightness, and especially those that differ from green, that is, worked land or ruins of mountains or their barrenness or stoniness.

Where the trees border on the air, they seem of one and the same colour, unless they are very near and of dense leaves, like the pine and similar trees.

When you see the trees from the side on which the sun illuminates them, you will see them of almost one same brightness, and the shadows within them will be occupied by the illuminated leaves that interpose between your eye and the shadows.

Nearby trees.

In the trees that interpose between the sun and the eye, beyond the shadows that spread toward their centre, one will see the green of their transparent leaves. That transparency will be interrupted in many parts by the shadowed leaves and branches that interpose between you and them, and in their upper parts they will be accompanied by many highlights of leaves.