Refreshing Cay Sky

Old French refreschir, to make fresh again — present-participle of refresh. As a color modifier, refreshing implies a clear-and-cool-and-revitalizing quality, the crisp color of Cornish-coast and Hebridean-island fresh-sea-air-and-cool-water revitalization. Sits at the crisp-and-cool end of the grid, parallel to fresh and bracing in usage.

Spanish cayo via Taíno cayo, low-island. As a color modifier, cay implies a tropical-coral-and-sand-spit quality, the visual register of Caribbean-and-Bahamian small low-tide reef-and-sand-spit sun-bleached-coral coastal surfaces in turquoise-water shallow-tropical light. Sits at the modifier-and-place end of the grid, parallel to isle and spit 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.