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Energetic Spring

#66cc60
Notes

Energetic Spring (#66CC60) is a true green 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 (117°, 51%, 59%) 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 violet. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#66cc60
RGB
rgb(102, 204, 96)
HSL
hsl(117, 51%, 59%)
HWB
hwb(117 38% 20%)
OKLCH
oklch(75.9% 0.175 142.6)
P3
color(display-p3 0.5026 0.7907 0.4269)
HSV
hsv(117, 53%, 80%)
LAB
lab(74.10% -51.03 44.43)
LCH
lch(74.10% 67.66 138.96)
CMYK
cmyk(50%, 0%, 53%, 20%)

Etymology

Energetic
adjective

Greek energētikós, active — derived from energeia (activity). As a color modifier, energetic implies a saturated-and-kinetic-and-active quality where the hue carries visual vibration and movement-suggestion that engages the eye dynamically. Sits at the bright-and-active end of the grid, parallel to dynamic and spirited in usage.

Spring
noun

The season — and the color of the new chlorophyll that appears with it. Spring green refers to the saturated, slightly yellow-shifted green of a temperate-zone canopy in early May: a clean, optically bright green with the translucent quality of new leaf tissue against the sun. Cooler than chartreuse, lighter than fern, with the seasonal optimism of a color that lasts only the few weeks before summer settles in.

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.

#66cc60
Original
#d0bc56
Protanopia
#c2b368
Deuteranopia
#59c7b4
Tritanopia
#afafaf
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
2.02:1
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
10.37:1

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
##66CC60
Display P3
Display P3
color(display-p3 0.5026 0.7907 0.4269)
P3 has subtle headroomOKLCH chroma 0.175

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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