Practical Fluff Sky

Greek praktikós, practical — adjectival suffix -al. As a color modifier, practical implies a clear-and-purpose-fit-and-everyday quality where the hue carries the visual register of Shaker-and-Quaker utilitarian-and-functional everyday-life craft. Sits at the crisp-and-functional end of the grid, parallel to functional and workmanlike in usage.

Imitative-onomatopoeic origin, attested c. 1790. As a color modifier, fluff implies a soft-puffed-and-airy quality, the visual register of cotton-and-down-and-wool-fluff hand-carded-and-puffed cotton-and-down-and-wool-fluff hand-carded-and-puffed-fluff surfaces under hand-carded-and-puffed cotton-and-down-and-wool-fluff working-light. Sits at the modifier-and-texture end of the grid, parallel to down and fuzz 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.