Vivid Hail Sky

From the Latin vividus, full of life — used as a color modifier since the late sixteenth century for hues that read as luminous and saturated. Vivid red, vivid blue: the implication is that the color appears almost lit from within, with the optical brightness of a high-chroma surface in good light. Sits at the bright-bucket center alongside bright and electric.

Old English hægl, hail-stones. As a color modifier, hail implies a hail-stone-and-clattering-and-spring-thunderstorm quality, the visual register of prairie-and-summer-thunderhead-hail hand-hail-stone-and-clattering-and-spring-thunderstorm prairie-and-summer-thunderhead-hail-and-Great-Plains hail-and-hail-stone-and-clattering surfaces under prairie-and-summer-thunderhead-hail-and-Great-Plains Tornado-Alley-and-Kansas-Oklahoma-storm-cell prairie-thunderhead-light. Sits at the modifier-and-weather end of the grid, parallel to sleet and flurry 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.