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Buttressed Isle Crimson

#a91a1b
Notes

Buttressed Isle Crimson (#A91A1B) is a true 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 (360°, 73%, 38%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. 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
#a91a1b
RGB
rgb(169, 26, 27)
HSL
hsl(360, 73%, 38%)
HWB
hwb(360 10% 34%)
OKLCH
oklch(47.4% 0.177 27.1)
P3
color(display-p3 0.6082 0.1647 0.1405)
HSV
hsv(360, 85%, 66%)
LAB
lab(36.47% 55.16 38.31)
LCH
lch(36.47% 67.16 34.78)
CMYK
cmyk(0%, 85%, 84%, 34%)

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.

Isle
modifier

Old French isle via Latin insula, island. As a color modifier, isle implies a small-and-self-contained quality, the visual register of Hebridean-and-Aegean small-island remote-and-windswept fishing-and-crofting hand-built community surfaces against the encircling sea. Sits at the modifier-and-place end of the grid, parallel to cay and strand in usage.

Crimson
noun

From the Old Spanish cremesin, itself from the Arabic qirmiz — the kermes scale insect, dried and ground into a brilliant carmine dye prized in the medieval Mediterranean. For centuries the most expensive red on a draper's shelf, reserved for cardinals, kings, and the cloth that gave English the word crimson. Cooler than scarlet, deeper than rose; the color of pomegranate seeds and a serious occasion.

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.

#a91a1b
Original
#4a4219
Protanopia
#6d6113
Deuteranopia
#bb001d
Tritanopia
#383838
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
7.37:1
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
2.85:1

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
##A91A1B
Display P3
Display P3
color(display-p3 0.6082 0.1647 0.1405)
P3 has subtle headroomOKLCH chroma 0.177

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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