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Buttressed Vermillion

#a6170b
Notes

Buttressed Vermillion (#A6170B) 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 (5°, 88%, 35%) places it in the highly saturated band at a mid 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
#a6170b
RGB
rgb(166, 23, 11)
HSL
hsl(5, 88%, 35%)
HWB
hwb(5 4% 35%)
OKLCH
oklch(46.5% 0.178 29.9)
HSV
hsv(5, 93%, 65%)
LAB
lab(35.49% 54.67 44.80)
LCH
lch(35.49% 70.69 39.33)
CMYK
cmyk(0%, 86%, 93%, 35%)

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.

Vermillion
noun

From the medieval Latin vermiculus, little worm — originally the kermes insect again, before the name transferred to ground cinnabar (mercury sulfide) when that pigment displaced kermes for warm reds. The color of Roman frescoes, Chinese imperial seals, the lacquered shrines of Kyoto. Brighter than crimson, hotter than scarlet, with the slight orange edge characteristic of the mineral source.

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

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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.

#a6170b
Original
#494005
Protanopia
#6b5e00
Deuteranopia
#b80017
Tritanopia
#353535
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
7.64:1
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
2.75:1

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