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Stable Indigobird

#51bde9
Notes

Stable Indigobird (#51BDE9) 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 (197°, 78%, 62%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#51bde9
RGB
rgb(81, 189, 233)
HSL
hsl(197, 78%, 62%)
HWB
hwb(197 32% 9%)
OKLCH
oklch(75.3% 0.116 228.2)
P3
color(display-p3 0.4341 0.7319 0.8963)
HSV
hsv(197, 65%, 91%)
LAB
lab(72.24% -17.62 -31.04)
LCH
lch(72.24% 35.69 240.41)
CMYK
cmyk(65%, 19%, 0%, 9%)

Etymology

Stable
adjective

Latin stabilis, standing-firm — sharing root with stand. As a color modifier, stable implies a clear-and-firm-and-unchanging quality where the hue carries the visual register of resistant-to-modulation-and-fade pigmentation. Sits at the crisp-and-firm end of the grid, parallel to steady and settled in usage.

Indigobird
noun

The genus Vidua — African parasitic finches whose males display saturated indigo-blue plumage in breeding season. The color refers to a male V. chalybeata (village indigobird) in breeding plumage: a saturated, slightly cool deep blue-violet with the iridescent satin finish of structural feather color.

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.

#51bde9
Original
#a6baeb
Protanopia
#91aae8
Deuteranopia
#00cacb
Tritanopia
#a9a9a9
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
2.14:1
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
9.81:1

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
##51BDE9
Display P3
Display P3
color(display-p3 0.4341 0.7319 0.8963)
P3 has subtle headroomOKLCH chroma 0.116

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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