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Bold Fei

#e51e00
Notes

Bold Fei (#E51E00) is a true red with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (8°, 100%, 45%) 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
#e51e00
RGB
rgb(229, 30, 0)
HSL
hsl(8, 100%, 45%)
HWB
hwb(8 0% 10%)
OKLCH
oklch(58.8% 0.230 30.9)
P3
color(display-p3 0.8248 0.2167 0.1249)
HSV
hsv(8, 100%, 90%)
LAB
lab(49.00% 70.48 62.38)
LCH
lch(49.00% 94.12 41.51)
CMYK
cmyk(0%, 87%, 100%, 10%)

Etymology

Bold
adjective

Old English beald, brave, courageous — a quality word that crossed over to color in the late seventeenth century. Bold describes a color that asserts itself: high saturation combined with mid lightness, where the hue presents itself without compromise. Sits at the center of the bold-bucket grid, near strong and rich. Closer to a presence word than a pigment word.

Fei
noun

A bright, slightly cool red used in Chinese textile tradition for the inner robes of Tang-dynasty court officials. The color refers to a fei-dyed silk: a saturated, slightly cool red with the satin finish of plant-dye-on-silk. Cooler than hong, brighter than jiang. The Chinese cousin of karakurenai.

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.

#e51e00
Original
#665900
Protanopia
#958300
Deuteranopia
#fd001e
Tritanopia
#464646
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).
AAon White
4.65:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
4.52:1

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
##E51E00
Display P3
Display P3
color(display-p3 0.8248 0.2167 0.1249)
P3 has visible headroomOKLCH chroma 0.230

This color is chromatic enough that authoring it as P3 native (instead of clamping to sRGB) gives a perceptibly more saturated render on wide-gamut displays — modern Macs, iPhones, iPads, and most recent OLED laptops.

Related Colors

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