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Cool Bark Lagoon

#21bbdc
Notes

Cool Bark Lagoon (#21BBDC) 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 (191°, 74%, 50%) 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
#21bbdc
RGB
rgb(33, 187, 220)
HSL
hsl(191, 74%, 50%)
HWB
hwb(191 13% 14%)
OKLCH
oklch(73.3% 0.126 217.3)
P3
color(display-p3 0.3504 0.7227 0.8477)
HSV
hsv(191, 85%, 86%)
LAB
lab(70.19% -26.21 -27.20)
LCH
lch(70.19% 37.78 226.06)
CMYK
cmyk(85%, 15%, 0%, 14%)

Etymology

Cool
adjective

Old English cōl, of low temperature — used as a color modifier as the complement to warm. Cool gray, cool blue: the optical impression of a slight blue-green shift, even within otherwise warm or neutral hues. Sits across the crisp, hushed, pale, and neutral buckets.

Bark
modifier

Old Norse bǫrkr, bark. As a color modifier, bark implies a tree-bark-and-rough-and-cork quality, the visual register of birch-and-oak-and-cork-bark hand-stripped-and-cork-bark birch-and-oak-and-cork-tree-bark hand-stripped-tree-bark surfaces under birch-and-oak-and-cork-bark hand-stripped-bark forest light. Sits at the modifier-and-texture end of the grid, parallel to rough and cane 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.

#21bbdc
Original
#a5b5de
Protanopia
#8ea4dc
Deuteranopia
#00c6c5
Tritanopia
#9d9d9d
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
2.28:1
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
9.21:1

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
##21BBDC
Display P3
Display P3
color(display-p3 0.3504 0.7227 0.8477)
P3 has subtle headroomOKLCH chroma 0.126

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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