Pure Robe Indigo

Latin purus, clean, unmixed — applied to color since antiquity for hues that contain only one pigment without dilution by white, black, or another color. Pure red is the textbook ideal: high saturation, mid lightness, no shift. Sits at the bold-bucket center, parallel to true and strong.

Old French robe, long-flowing-garment. As a color modifier, robe implies a long-flowing-and-academic-and-judicial quality, the visual register of Oxford-Cambridge-academic-and-judicial-robe hand-long-flowing-and-academic-and-judicial Oxford-Cambridge-academic-and-judicial-robe-and-monastic-habit robe-and-long-flowing-and-academic surfaces under Oxford-Cambridge-academic-and-judicial-robe-and-monastic-habit Senate-and-Inns-of-Court-and-cathedral-cloister Trinity-Senior-Common-Room-light. Sits at the modifier-and-textile end of the grid, parallel to gown and cope in usage.

Indigofera tinctoria, the South Asian legume whose leaves yield the deep blue dye that has clothed humanity for at least four thousand years — Egyptian linen, Mayan textile, the slave-grown plantations of Carolina. The color refers to a freshly indigo-dyed cotton thread: a saturated, slightly violet-shifted deep blue with the slight lustre of a fiber surface oxidized in air. Deeper than cobalt, cooler than royal.