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Stable Sirocco Verdigris

#21b5b7
Notes

Stable Sirocco Verdigris (#21B5B7) 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 (181°, 69%, 42%) 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
#21b5b7
RGB
rgb(33, 181, 183)
HSL
hsl(181, 69%, 42%)
HWB
hwb(181 13% 28%)
OKLCH
oklch(70.3% 0.114 196.3)
P3
color(display-p3 0.3399 0.6995 0.7117)
HSV
hsv(181, 82%, 72%)
LAB
lab(67.12% -34.96 -11.55)
LCH
lch(67.12% 36.82 198.27)
CMYK
cmyk(82%, 1%, 0%, 28%)

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.

Sirocco
modifier

Arabic sharq, eastern-or-Saharan-wind. As a color modifier, sirocco implies a hot-Saharan-and-Mediterranean-wind quality, the visual register of Saharan-and-Sicilian-and-Maltese-sirocco hand-hot-Saharan-and-Mediterranean-wind Saharan-and-Sicilian-and-Maltese-sirocco-and-North-African sirocco-and-hot-Saharan-and-Mediterranean-wind surfaces under Saharan-and-Sicilian-and-Maltese-sirocco-and-North-African Sahara-and-Sicily-and-Malta-and-Tunis hot-North-African-wind-light. Sits at the modifier-and-weather end of the grid, parallel to mistral and zephyr in usage.

Verdigris
noun

The basic copper carbonate that forms on weathered copper and bronze — the pigment scraped from oxidized metal and used in Renaissance painting before being supplanted by more stable greens. The color refers to a thick verdigris on aged copper roofing or the Statue of Liberty's surface: a soft, slightly muted blue-green with the powdery finish of mineral oxide. Cooler than patina, warmer than seafoam, with the archaeological weight of a mineral made by time.

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.

#21b5b7
Original
#a8acb7
Protanopia
#949db8
Deuteranopia
#00bbb5
Tritanopia
#969696
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
2.51:1
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
8.36:1

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
##21B5B7
Display P3
Display P3
color(display-p3 0.3399 0.6995 0.7117)
P3 has subtle headroomOKLCH chroma 0.114

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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