Glistening Glen Sky

Old English glisnian, to glisten — present-participle of glisten, sharing root with German glitzern. As a color modifier, glistening implies a saturated-and-wet-or-polished-reflective quality, the bright color of fresh-rain-and-polished-silver surface-reflection. Sits at the bright-and-reflective end of the grid, parallel to shimmering and gleaming in usage.

Scottish-Gaelic gleann, narrow valley between hills. As a color modifier, glen implies a sheltered-and-mossy quality, the visual register of Scottish-Highland deep-cut river-valleys with peat-water-and-bracken hand-cut shieling-and-bothy crofting-life surfaces under Highland-and-overcast sky. Sits at the modifier-and-place end of the grid, parallel to vale and dell 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.