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Booming Fast Crimson

#a71d21
Notes

Booming Fast Crimson (#A71D21) 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 (358°, 70%, 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
#a71d21
RGB
rgb(167, 29, 33)
HSL
hsl(358, 70%, 38%)
HWB
hwb(358 11% 35%)
OKLCH
oklch(47.2% 0.173 25.8)
P3
color(display-p3 0.6012 0.1707 0.1574)
HSV
hsv(358, 83%, 65%)
LAB
lab(36.38% 54.01 34.71)
LCH
lch(36.38% 64.20 32.73)
CMYK
cmyk(0%, 83%, 80%, 35%)

Etymology

Booming
adjective

Imitative-onomatopoeic origin — present-participle of boom, sharing root with Dutch bommen. As a color modifier, booming implies a saturated-and-loud-and-confident quality where the hue announces itself with full visual amplitude. Sits at the bold-and-resonant end of the grid, parallel to resounding and thunderous.

Fast
modifier

Old English fæst, abstinence-from-food. As a color modifier, fast implies a Lenten-and-fasting-and-restraint quality, the visual register of Roman-Catholic-and-Eastern-Orthodox-Fast Lenten-and-Ramadan-fasting religious-fast-and-restraint austere surfaces under fasting-and-restraint austere ecclesiastical light. Sits at the modifier-and-time end of the grid, parallel to lent and vigil 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.

#a71d21
Original
#4a431f
Protanopia
#6c601b
Deuteranopia
#b80021
Tritanopia
#3b3b3b
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
7.39:1
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
2.84:1

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
##A71D21
Display P3
Display P3
color(display-p3 0.6012 0.1707 0.1574)
P3 has subtle headroomOKLCH chroma 0.173

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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