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Sharp Cerulean

#01b2df
Notes

Sharp Cerulean (#01B2DF) is a true cyan with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (192°, 99%, 44%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#01b2df
RGB
rgb(1, 178, 223)
HSL
hsl(192, 99%, 44%)
HWB
hwb(192 0% 13%)
OKLCH
oklch(71.0% 0.134 224.3)
P3
color(display-p3 0.3119 0.6875 0.8565)
HSV
hsv(192, 100%, 87%)
LAB
lab(67.41% -21.95 -33.17)
LCH
lch(67.41% 39.77 236.51)
CMYK
cmyk(100%, 20%, 0%, 13%)

Etymology

Sharp
adjective

Old English scearp, cutting, pointed — applied metaphorically to color since the seventeenth century for hues that read as definite and edge-defined. Sharp red, sharp green: the implication is saturation combined with high-contrast crispness. Sits in the bright-bucket center alongside crisp and clear, with a slightly more incisive edge.

Cerulean
noun

From the Latin caeruleum, originally referring to dark blue paint pigment of the Roman world, then via French céruléen into English. As a modern art-supply name, cerulean blue is the cobalt-tin oxide pigment introduced in 1805. The color refers to a clean, slightly green-shifted blue with the matte finish of mineral pigment in linseed oil: lighter than cobalt, deeper than aqua, with the painter's weight of a word for sky.

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.

#01b2df
Original
#99aee1
Protanopia
#809cde
Deuteranopia
#00bfc1
Tritanopia
#909090
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).
Failon White
2.49:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
8.43:1

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
##01B2DF
Display P3
Display P3
color(display-p3 0.3119 0.6875 0.8565)
P3 has subtle headroomOKLCH chroma 0.134

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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