Pleasant Knot Sky

From the French plaisant, pleasing — used as a color modifier since the fifteenth century for hues that read as agreeable, the kind of color that wears well over a long viewing without becoming demanding or fatiguing. Pleasant green, pleasant rose: moderate saturation combined with optical comfort. Sits at the crisp-bucket alongside easy and calm.

Old English cnotta, knot. As a color modifier, knot implies a sailor's-rope-knot quality, the visual register of Royal-Navy-and-merchant-marine-knot hand-tied sailor's-rope-and-line bowline-and-figure-eight-and-clove-hitch maritime-rigging surfaces under tall-ship-and-frigate sailor's-knot-and-line working light. Sits at the modifier-and-nautical end of the grid, parallel to sheet and spar 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.