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Sure Tropics

#51bd98
Notes

Sure Tropics (#51BD98) is a true teal 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 (159°, 45%, 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 magenta. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#51bd98
RGB
rgb(81, 189, 152)
HSL
hsl(159, 45%, 53%)
HWB
hwb(159 32% 26%)
OKLCH
oklch(72.5% 0.114 167.7)
P3
color(display-p3 0.4341 0.7319 0.6048)
HSV
hsv(159, 57%, 74%)
LAB
lab(69.76% -39.94 9.48)
LCH
lch(69.76% 41.05 166.64)
CMYK
cmyk(57%, 0%, 20%, 26%)

Etymology

Sure
adjective

Old French seur, certain — used as a color modifier since the medieval period for hues that read as confident and stable. Sure red, sure blue: moderate saturation combined with optical commitment. Sits at the crisp-bucket center alongside steady and true.

Tropics
noun

The Earth's equatorial belt between the Tropic of Cancer and the Tropic of Capricorn — the region of the world where the sun reaches direct overhead at some point of the year. Tropics refers to the unifying blue-green of tropical-zone ocean and lagoon water: a saturated, slightly cool deep blue-green.

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.

#51bd98
Original
#b9b196
Protanopia
#a9a69a
Deuteranopia
#16beb2
Tritanopia
#a3a3a3
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
2.31:1
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
9.08:1

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
##51BD98
Display P3
Display P3
color(display-p3 0.4341 0.7319 0.6048)
P3 has subtle headroomOKLCH chroma 0.114

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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