True Hull Sky

Old English trēowe, faithful — used as a color modifier since the seventeenth century for hues that read as the canonical version of their family. True red, true blue: the saturation is full, the hue is neither shifted nor adulterated. Sits at the center of the bold and crisp buckets, marking the unequivocal middle of any chromatic family.

Old English hulu, husk / shell. As a color modifier, hull implies a ship's-body-and-skin quality, the visual register of Royal-Navy-and-merchant-marine-hull hand-laid clinker-and-carvel-built timber-and-iron-and-steel ship's-hull-and-skin maritime-architecture surfaces under ship-hull-and-waterline maritime-and-dry-dock light. Sits at the modifier-and-nautical end of the grid, parallel to keel and prow 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.