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Heartening Nebula Lagoon

#39c4dd
Notes

Heartening Nebula Lagoon (#39C4DD) 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°, 71%, 55%) 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
#39c4dd
RGB
rgb(57, 196, 221)
HSL
hsl(189, 71%, 55%)
HWB
hwb(189 22% 13%)
OKLCH
oklch(75.8% 0.119 212.6)
HSV
hsv(189, 74%, 87%)
LAB
lab(73.26% -28.18 -23.02)
LCH
lch(73.26% 36.39 219.24)
CMYK
cmyk(74%, 11%, 0%, 13%)

Etymology

Heartening
adjective

Old English heorte (heart) — present-participle of hearten. As a color modifier, heartening implies a clear-and-uplifting-and-encouraging quality where the hue carries the visual register of cheerful-encouraging color-tone. Sits at the crisp-and-cheerful end of the grid, parallel to welcoming and cheerful in usage.

Nebula
modifier

Latin nebula, mist-or-cloud. As a color modifier, nebula implies a glowing-cloud-and-stellar-cradle quality, the visual register of Orion-and-Eagle-Nebula hand-glowing-cloud-and-stellar-cradle Orion-and-Eagle-and-Crab-Nebula nebula-and-glowing-cloud-and-stellar-cradle surfaces under Orion-and-Eagle-and-Crab-Nebula Hubble-and-James-Webb-deep-field stellar-cradle-light. Sits at the modifier-and-cosmic end of the grid, parallel to plasma and meteor 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

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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.

#39c4dd
Original
#b1bdde
Protanopia
#9aaddd
Deuteranopia
#00cecc
Tritanopia
#a8a8a8
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
2.08:1
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
10.11:1

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