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Assured Zest Crimson

#a51d18
Notes

Assured Zest Crimson (#A51D18) 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 (2°, 75%, 37%) 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
#a51d18
RGB
rgb(165, 29, 24)
HSL
hsl(2, 75%, 37%)
HWB
hwb(2 9% 35%)
OKLCH
oklch(46.8% 0.172 28.4)
P3
color(display-p3 0.5940 0.1694 0.1315)
HSV
hsv(2, 85%, 65%)
LAB
lab(35.88% 53.16 39.06)
LCH
lch(35.88% 65.96 36.31)
CMYK
cmyk(0%, 82%, 85%, 35%)

Etymology

Assured
adjective

Old French aseürer, to give assurance — past-participle of assure. As a color modifier, assured implies a saturated-and-confident quality where the hue carries unwavering certainty about its own visual identity. Sits at the bold-and-confident end of the grid, parallel to certain and poised.

Zest
modifier

French zeste, citrus-peel-and-bright-tang. As a color modifier, zest implies a bright-citrus-peel-and-aromatic-oil quality, the visual register of Provençal-and-Sicilian-citrus-zest hand-bright-citrus-peel-and-aromatic-oil Provençal-and-Sicilian-citrus-zest-and-Mediterranean-bergamot zest-and-bright-citrus-peel surfaces under Provençal-and-Sicilian-citrus-zest-and-Mediterranean-bergamot Menton-and-Sicily-and-Calabria-citrus-grove citrus-grove-light. Sits at the modifier-and-flavor end of the grid, parallel to tang and bergamot 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.

#a51d18
Original
#4a4115
Protanopia
#6b5f0f
Deuteranopia
#b6001e
Tritanopia
#3a3a3a
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
7.53:1
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
2.79:1

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
##A51D18
Display P3
Display P3
color(display-p3 0.5940 0.1694 0.1315)
P3 has subtle headroomOKLCH chroma 0.172

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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