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Effective Smock Lagoon

#21afc8
Notes

Effective Smock Lagoon (#21AFC8) 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 (189°, 72%, 46%) 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
#21afc8
RGB
rgb(33, 175, 200)
HSL
hsl(189, 72%, 46%)
HWB
hwb(189 13% 22%)
OKLCH
oklch(69.5% 0.116 213.4)
P3
color(display-p3 0.3293 0.6763 0.7718)
HSV
hsv(189, 84%, 78%)
LAB
lab(65.87% -26.73 -22.85)
LCH
lch(65.87% 35.16 220.52)
CMYK
cmyk(84%, 12%, 0%, 22%)

Etymology

Effective
adjective

Latin effectīvus, productive — adjectival suffix -ive. As a color modifier, effective implies a clear-and-purpose-achieving quality where the hue carries the visual register of successful-task-completion design-element. Sits at the crisp-and-functional end of the grid, parallel to practical and useful in usage.

Smock
modifier

Old English smoc, loose-shift-or-shepherd's-smock. As a color modifier, smock implies a shepherd's-smock-and-artist's-smock-and-pleated quality, the visual register of English-shepherd's-smock-and-artist's-smock hand-shepherd's-smock-and-artist's-smock-and-pleated English-shepherd's-smock-and-artist's-smock-and-Sussex-Surrey-rural smock-and-shepherd's-smock surfaces under English-shepherd's-smock-and-artist's-smock-and-Sussex-Surrey-rural Sussex-Downs-and-Surrey-village shepherd-and-painter-light. Sits at the modifier-and-textile end of the grid, parallel to frock and tunic in usage.

Lagoon
noun

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.

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.

#21afc8
Original
#9da9c9
Protanopia
#8799c8
Deuteranopia
#00b9b7
Tritanopia
#939393
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
2.61:1
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
8.03:1

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
##21AFC8
Display P3
Display P3
color(display-p3 0.3293 0.6763 0.7718)
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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