The blue of distant trees and the sun on the forest
How aerial haze tints distant woods sky-blue in their shadows, and how sunlight sharpens and thins the look of trees
A leaf from the sixth book of the Treatise on Painting, on rendering trees at a distance. It explains that the azure of remote trees arises in their shadowed parts, where the intervening lit air is tinged sky-blue, while their sunlit parts are the last to lose their green. A lettered chapter argues that when the sun lights a forest the trees show defined lights and shadows and seem nearer, their thin leaves glowing by transparency, and that sunlit trees carry fewer highlights than sky-lit ones because the sky is the larger light source. A further chapter contrasts the brightness of near versus remote greenery. The page is wholly text on this leaf, carrying only the running head and folio number besides the transcribed matter.
On this page
Distant trees turn blue in shadow, keep green in light
The azure that trees acquire in remote places is generated more in the darkness than toward the luminous parts, arising from the light of the intervening air, which is tinged sky-blue. The luminous parts of the trees are the last to lose their greenness.
The sun lighting the forest: defined shade and glowing thin leaves
When the sun illuminates the forest, the trees show defined shadows and lights and so seem to have come nearer, taking on more recognizable form. What the sun does not reach appears equally dark, except thin leaves between sun and eye that glow by transparency; sunlit trees carry fewer highlights than sky-lit ones, because the sky is the larger light source.
Sparse, thin-leaved trees seem thinner as their shadow withdraws
As the shadows of plants shrink, sparse, thin-leaved trees such as peach and plum appear thinner still, because their shadow withdraws toward the middle of the plant, so that the plant seems diminished and the outlying branches read as one color with the background.
Near greenery shows brighter lights and darker shadows than remote
The luminous parts of the greenery of plants near the eye appear brighter than those of remote plants, and their shadowed parts appear darker; remote plants, by contrast, show their luminous parts darker.