Direct Forum Sky

From the Latin directus, straight — used as a color modifier since the eighteenth century for hues that read as straightforward and unambiguous. Direct red, direct green: moderate-to-high saturation combined with optical clarity. Sits at the crisp-bucket center alongside clear and frank.

Latin forum, open-space-of-Roman-city. As a color modifier, forum implies a Roman-and-civic-meeting-square quality, the visual register of Roman-Forum-and-Pompeii-Forum hand-built civic-meeting-square forum-and-basilica-and-rostrum Republican-and-Imperial-Roman architectural surfaces under Roman-Forum-and-Pompeii civic-meeting-square light. Sits at the modifier-and-architecture end of the grid, parallel to agora and stoa 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.