Rich Neptune Cerulean

Old French riche, wealthy, abundant — applied to color since the medieval period for hues that read as plentiful in pigment. Rich red, rich brown: the implication is depth combined with saturation, a color that gives the eye more to absorb. Sits at the saturated mid-light corner of the engine's grid, slightly warmer than bold and deeper than vivid.

Latin Neptunus, Roman-god-of-sea-and-eighth-planet. As a color modifier, neptune implies a Roman-god-of-sea-and-deep-blue-eighth-planet quality, the visual register of Roman-Neptune-and-Voyager-2-deep-blue hand-Roman-god-of-sea-and-deep-blue-eighth-planet Roman-Neptune-and-Voyager-2-deep-blue-and-Trevi-Fountain neptune-and-Roman-god-of-sea surfaces under Roman-Neptune-and-Voyager-2-deep-blue-and-Trevi-Fountain Voyager-2-flyby-and-Trevi-Fountain deep-blue-planet-light. Sits at the modifier-and-zodiac end of the grid, parallel to uranus and saturn in usage.

From the Latin caeruleum, originally referring to dark blue paint pigment of the Roman world, then via French céruléen into English. As a modern art-supply name, cerulean blue is the cobalt-tin oxide pigment introduced in 1805. The color refers to a clean, slightly green-shifted blue with the matte finish of mineral pigment in linseed oil: lighter than cobalt, deeper than aqua, with the painter's weight of a word for sky.