Subterranean Prism Ultramarine

Latin sub-terraneus, under-ground. As a color modifier, subterranean implies the cool deep darkness of cave-and-tunnel interiors where ambient daylight has been completely eliminated. Sits at the deep-and-cool end of the grid, where the hue reads as cellar-dwelling rather than night-sky deep.

Greek πρῖσμα, something-sawn. As a color modifier, prism implies a Newtonian-rainbow-and-spectrum-splitting quality, the visual register of Newton-Optics-and-Cambridge-prism hand-Newtonian-rainbow-and-spectrum-splitting Newton-Optics-and-Cambridge-and-Trinity-College-prism prism-and-Newtonian-rainbow-and-spectrum-splitting surfaces under Newton-Optics-and-Cambridge-and-Trinity-College-prism 17th-century-natural-philosophy-and-rainbow-experiment spectrum-light. Sits at the modifier-and-cosmic end of the grid, parallel to corona and plasma in usage.

The pigment ground from lapis lazuli — the Afghan mineral imported through Venice in the late Middle Ages, more expensive by weight than gold during the Renaissance. The color refers to a freshly mixed ultramarine pigment in linseed oil: a saturated, slightly violet-shifted deep blue with the matte finish of micron-ground rock. Deeper than cobalt, cooler than royal, with the art-historical weight of the blue Vermeer reserved for Mary's robe.