Quickening Spring
Quickening Spring (#66BD5A) 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 (113°, 43%, 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 violet. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old English cwic, living / lively — present-participle of quicken. As a color modifier, quickening implies a saturated-and-coming-alive-and-active quality where the hue accelerates visual engagement. Sits at the bright-and-active end of the grid, parallel to animated and invigorating in usage.
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 exploreHarmonies
Accessibility
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.
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.
Wide gamut
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.
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.