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Coolcyan

Plush Aqua Crystal

#51bdd1
Notes

Plush Aqua Crystal (#51BDD1) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (189°, 58%, 57%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#51bdd1
RGB
rgb(81, 189, 209)
HSL
hsl(189, 58%, 57%)
HWB
hwb(189 32% 18%)
OKLCH
oklch(74.4% 0.102 211.7)
HSV
hsv(189, 61%, 82%)
LAB
lab(71.38% -24.89 -19.30)
LCH
lch(71.38% 31.49 217.79)
CMYK
cmyk(61%, 10%, 0%, 18%)

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

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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.

#51bdd1
Original
#adb7d2
Protanopia
#9aa9d1
Deuteranopia
#00c5c3
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
2.20:1
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
9.55:1

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Canvas