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Lucid Forum Lagoon

#40bdd6
Notes

Lucid Forum Lagoon (#40BDD6) 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 (190°, 65%, 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
#40bdd6
RGB
rgb(64, 189, 214)
HSL
hsl(190, 65%, 55%)
HWB
hwb(190 25% 16%)
OKLCH
oklch(74.1% 0.112 213.9)
P3
color(display-p3 0.3995 0.7312 0.8267)
HSV
hsv(190, 70%, 84%)
LAB
lab(71.10% -26.00 -22.49)
LCH
lch(71.10% 34.38 220.86)
CMYK
cmyk(70%, 12%, 0%, 16%)

Etymology

Lucid
adjective

Latin lūcidus, clear / bright — derived from lūx (light). As a color modifier, lucid implies a clear-and-readable quality where the hue is unambiguous and free of optical clutter. Sits at the crisp-and-clear end of the grid, parallel to pellucid and plain in usage.

Forum
modifier

Latin forum, open-space-of-Roman-city. As a color modifier, forum implies a Roman-and-civic-meeting-square quality, the visual register of Roman-Forum-and-Pompeii-Forum hand-built civic-meeting-square forum-and-basilica-and-rostrum Republican-and-Imperial-Roman architectural surfaces under Roman-Forum-and-Pompeii civic-meeting-square light. Sits at the modifier-and-architecture end of the grid, parallel to agora and stoa 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.

#40bdd6
Original
#abb7d7
Protanopia
#96a7d6
Deuteranopia
#00c7c5
Tritanopia
#a4a4a4
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
2.22:1
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
9.47:1

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
##40BDD6
Display P3
Display P3
color(display-p3 0.3995 0.7312 0.8267)
P3 has subtle headroomOKLCH chroma 0.112

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.

Related Colors

Canvas