Serene Arbor Sky

Latin serēnus, clear / unclouded. As a color modifier, serene implies a clear-and-untroubled quality where the hue carries the visual register of cloudless-bright-day atmospheric stability. Sits at the crisp-and-calm end of the grid, parallel to placid and untroubled in usage.

Latin arbor, tree-or-trunk. As a color modifier, arbor implies a Latin-tree-and-vine-arbor quality, the visual register of Pliny-Natural-History-and-Roman-villa-arbor hand-Latin-tree-and-vine-arbor Pliny-Natural-History-and-Roman-villa-arbor-and-pergola arbor-and-Latin-tree-and-vine-arbor surfaces under Pliny-Natural-History-and-Roman-villa-arbor-and-pergola Pompeii-and-Tuscan-pergola-and-grape-arbor leafy-shade-light. Sits at the modifier-and-Latin end of the grid, parallel to via and domus in usage.

The blue of a clear sky at noon — produced by Rayleigh scattering, the preferential dispersion of shorter wavelengths through atmospheric molecules. Air itself is colorless; the color we see is sunlight scattered toward our eyes by every cubic kilometer above. The reference shade is mid-latitude noon under a high pressure system: a clean, slightly green-shifted blue with the luminous depth of light scattered across an entire hemisphere of air.