Etched Wraith Sky

German ätzen, to etch — past-participle of etch. As a color modifier, etched implies a clear-and-precisely-incised quality, the crisp color of Rembrandt-and-Dürer hand-pulled etching-print fine-line incised-image. Sits at the crisp-and-incised end of the grid, parallel to engraved and inscribed in usage.

Scots wraith, ghost-or-apparition. As a color modifier, wraith implies a ghostly-and-pale-and-apparitional quality, the visual register of Highland-Scots-and-Border-Ballad-wraith hand-ghostly-and-pale-and-apparitional Highland-Scots-and-Border-Ballad-and-Hebridean wraith-and-ghostly-and-pale surfaces under Highland-Scots-and-Border-Ballad-and-Hebridean moonlit-and-mist-shrouded-and-pale graveyard-and-tarn-light. Sits at the modifier-and-mood end of the grid, parallel to pall and gloam 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.