Subterranean Phlox
Subterranean Phlox (#211C63) is a deep blue with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (244°, 56%, 25%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary yellow. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
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.
The genus Phlox — flame in Greek, for the brightness of its flower colors. P. subulata is the creeping moss phlox of rock gardens; P. paniculata is the tall summer-border phlox in cottage gardens. The color refers to a fresh blue-violet phlox cluster: a saturated, slightly violet-shifted blue-purple with the matte finish of densely packed five-petaled flowers. Cooler than wisteria, warmer than veronica.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.