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Effective Strand Lagoon

#3bb9d1
Notes

Effective Strand Lagoon (#3BB9D1) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (190°, 62%, 53%) 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
#3bb9d1
RGB
rgb(59, 185, 209)
HSL
hsl(190, 62%, 53%)
HWB
hwb(190 23% 18%)
OKLCH
oklch(72.8% 0.112 213.2)
P3
color(display-p3 0.3843 0.7156 0.8074)
HSV
hsv(190, 72%, 82%)
LAB
lab(69.63% -26.20 -22.01)
LCH
lch(69.63% 34.22 220.03)
CMYK
cmyk(72%, 11%, 0%, 18%)

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.

Strand
modifier

Old English strand, shore / beach. As a color modifier, strand implies a London-Thames-bank-and-Anglo-Saxon-shore quality, the visual register of London-Strand-and-North-Sea-coast tidal-shore-and-river-bank embankment-and-walking-promenade surfaces under London-Strand-and-North-Sea-coast tidal-edge atmospheric light. Sits at the modifier-and-place end of the grid, parallel to shore and coast 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.

#3bb9d1
Original
#a7b3d2
Protanopia
#92a4d1
Deuteranopia
#00c2c0
Tritanopia
#a0a0a0
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
2.32:1
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
9.05:1

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
##3BB9D1
Display P3
Display P3
color(display-p3 0.3843 0.7156 0.8074)
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.

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