Heartening Stir Sky

Old English heorte (heart) — present-participle of hearten. As a color modifier, heartening implies a clear-and-uplifting-and-encouraging quality where the hue carries the visual register of cheerful-encouraging color-tone. Sits at the crisp-and-cheerful end of the grid, parallel to welcoming and cheerful in usage.

Old English styrian, to-move-or-agitate. As a color modifier, stir implies a slow-moved-and-rippled-and-agitated quality, the visual register of cauldron-and-tea-cup-stir hand-slow-moved-and-rippled-and-agitated cauldron-and-tea-cup-and-pot-au-feu stirred-and-slow-moved-and-rippled-and-agitated surfaces under cauldron-and-tea-cup-and-pot-au-feu kitchen-hearth-and-witch's-fire-and-parlor-tea-table simmer-and-eddy-light. Sits at the modifier-and-mood end of the grid, parallel to swirl and eddy 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.