Frank Gloam Sky

From the Old French franc, free, sincere — used as a color modifier since the seventeenth century for hues that read as direct and unhedged. Frank red, frank brown: moderate-to-high saturation combined with optical directness. Sits at the crisp-bucket alongside direct and honest.

Old English glōm, twilight-or-dusk. As a color modifier, gloam implies a twilight-and-half-light-and-fading quality, the visual register of Scottish-Border-and-Hebridean-gloam hand-twilight-and-half-light-and-fading Scottish-Border-and-Hebridean-and-Orkney gloamed-and-twilight-and-fading surfaces under Scottish-Border-and-Hebridean-and-Orkney long-northern-twilight-and-blue-hour gloaming-and-twilight light. Sits at the modifier-and-mood end of the grid, parallel to dusk and shade 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.