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Effective Mater Lagoon

#31c5e7
Notes

Effective Mater Lagoon (#31C5E7) 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°, 79%, 55%) places it in the highly saturated band at a mid lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. 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
#31c5e7
RGB
rgb(49, 197, 231)
HSL
hsl(191, 79%, 55%)
HWB
hwb(191 19% 9%)
OKLCH
oklch(76.3% 0.127 217.7)
P3
color(display-p3 0.3877 0.7616 0.8904)
HSV
hsv(191, 79%, 91%)
LAB
lab(73.77% -26.36 -27.66)
LCH
lch(73.77% 38.21 226.38)
CMYK
cmyk(79%, 15%, 0%, 9%)

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.

Mater
modifier

Latin mater, mother. As a color modifier, mater implies a Latin-mother-and-Stabat-Mater-and-Madonna quality, the visual register of Stabat-Mater-and-Pietà-mater hand-Latin-mother-and-Stabat-Mater-and-Madonna Stabat-Mater-and-Pietà-mater-and-Marian-iconography mater-and-Latin-mother surfaces under Stabat-Mater-and-Pietà-mater-and-Marian-iconography Roman-and-Counter-Reformation Madonna-iconographic-light. Sits at the modifier-and-Latin end of the grid, parallel to pater and amor 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.

#31c5e7
Original
#afbfe9
Protanopia
#97aee7
Deuteranopia
#00d1d0
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
2.04:1
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
10.27:1

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
##31C5E7
Display P3
Display P3
color(display-p3 0.3877 0.7616 0.8904)
P3 has subtle headroomOKLCH chroma 0.127

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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