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Buttressed Hoar Ruby

#900f18
Notes

Buttressed Hoar Ruby (#900F18) is a deep red with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (356°, 81%, 31%) places it in the highly saturated band at a dark lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. For a confident two-color system, pair it with its complementary cyan. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#900f18
RGB
rgb(144, 15, 24)
HSL
hsl(356, 81%, 31%)
HWB
hwb(356 6% 44%)
OKLCH
oklch(41.8% 0.160 25.4)
P3
color(display-p3 0.5171 0.1225 0.1201)
HSV
hsv(356, 90%, 56%)
LAB
lab(30.25% 50.34 32.18)
LCH
lch(30.25% 59.75 32.59)
CMYK
cmyk(0%, 90%, 83%, 44%)

Etymology

Buttressed
adjective

Old French bouterez, thrusting-mass — past-participle of buttress, derived from bouter (to thrust). As a color modifier, buttressed implies a saturated-and-architecturally-supported quality, the deep-rich color of Gothic-Cathedral flying-buttress-and-rib-vault stone-architecture. Sits at the bold-and-fortified end of the grid, parallel to fortified and reinforced.

Hoar
modifier

Old English hār, grey-with-age-or-hoar-frost. As a color modifier, hoar implies a grey-aged-and-hoar-frosted quality, the visual register of English-meadow-and-hedgerow-hoar hand-grey-aged-and-hoar-frosted English-meadow-and-hedgerow-hoar-and-frosted-pasture hoar-and-grey-aged-and-hoar-frosted surfaces under English-meadow-and-hedgerow-hoar-and-frosted-pasture Cotswold-and-Yorkshire-Dales-frost-pasture frosted-meadow-light. Sits at the modifier-and-weather end of the grid, parallel to rime and sleet in usage.

Ruby
noun

From the Latin ruber — simply, red. The gemstone is a chromium-tinged corundum, harder than anything in nature except diamond, and so saturated that a fine Burmese pigeon's blood ruby at auction outpaces a comparable diamond by weight. The color borrows the gem's confidence: a clear, glassy red without the brown of garnet or the blue of crimson.

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 explore

Harmonies

Accessibility

Color-vision simulation

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.

#900f18
Original
#3c3617
Protanopia
#5b5111
Deuteranopia
#9f0015
Tritanopia
#2b2b2b
Achromatopsia
WCAG contrast

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.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon White
9.26:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon Black
2.27:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##900F18
Display P3
Display P3
color(display-p3 0.5171 0.1225 0.1201)
P3 has subtle headroomOKLCH chroma 0.160

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

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