Why Smoke and Dust Read Toward the Sun, and a Perspective Precept
The two causes of smoke and dust visibility, and aerial perspective when no light and dark vary in the air
The page explains why smoke and dust are seen toward the sun: its rays kindle the particles while the eastern roofs behind them stay shadowed, and the denser the smoke or dust the brighter it glows, dust reading darker than moist smoke. A separate note, 'Of smoke and dust', adds that against the bright ground of sunlit roofs smoke is little seen in the west. A 'Precept of perspective in painting' then teaches that where the air shows no variety of brightness or darkness, the perspective of shadows falls away and the painter must rely only on the diminution of bodies, of colours, and of the recognition of distant things.
On this page
The two causes by which smoke and dust are lit toward the sun
Smoke shows toward the east because the sun shines through its particles and makes them evident, while the obliquity of the eastern roofs behind it cannot be lit and stays shadowy. Dust behaves likewise, and both grow more luminous the denser they are, densest toward the middle; dust reads darker than moist smoke.
Perspective precept: when the air shows no light and dark
When you cannot recognise variety of brightness or darkness in the air, the perspective of shadows is driven from your imitation. The painter must then rely only on the diminution of bodies, the diminishing of colours, and the loss of the recognition of the figure of distant objects, which makes a thing appear more remote.