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Clear Aqua

#51bbe3
Notes

Clear Aqua (#51BBE3) 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 (196°, 72%, 60%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#51bbe3
RGB
rgb(81, 187, 227)
HSL
hsl(196, 72%, 60%)
HWB
hwb(196 32% 11%)
OKLCH
oklch(74.6% 0.112 226.2)
HSV
hsv(196, 64%, 89%)
LAB
lab(71.44% -18.44 -29.02)
LCH
lch(71.44% 34.38 237.56)
CMYK
cmyk(64%, 18%, 0%, 11%)

Etymology

Clear
adjective

From the Latin clarus, bright, distinct — used as a color modifier since the medieval period for hues without haze or mixing. Clear blue sky, clear green water: the implication is moderate saturation combined with optical clarity. Sits at the crisp-bucket center alongside clean and true.

Aqua
noun

Latin for water, borrowed into English as a color name in the early twentieth century — initially for the pale blue-green of swimming pools and tropical seas. The color refers to a clear-bottomed swimming pool in midday sun: a clean, slightly green-shifted light blue with the optical clarity of filtered water. Cooler than seafoam, lighter than turquoise, with the mid-century weight of a word that paints itself across postwar interior decor.

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.

#51bbe3
Original
#a5b7e5
Protanopia
#91a8e3
Deuteranopia
#00c7c8
Tritanopia
#a7a7a7
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
2.19:1
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
9.57:1

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