Lustrous Sap
Lustrous Sap (#66BE17) is a true lime with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (92°, 78%, 42%) 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 indigo. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
From the Latin lustrare, to illuminate — used as a color word since the seventeenth century for hues with the slight specular shine of polished metal or silk. Lustrous green, lustrous gold: the implication is moderate-to-high saturation combined with surface reflectivity. Sits at the bright-and-glossy corner alongside gleaming.
The watery solution that moves through xylem and phloem in vascular plants — sugars, amino acids, ions, and the occasional alkaloid. The color refers to fresh-cut grass sap or unconcentrated maple sap: a clear, slightly yellow-green with the optical quality of plant fluid. Lighter than chartreuse, cooler than wheat, with the green-tinged clarity of liquid that has just stopped being living tissue.
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.
This color is chromatic enough that authoring it as P3 native (instead of clamping to sRGB) gives a perceptibly more saturated render on wide-gamut displays — modern Macs, iPhones, iPads, and most recent OLED laptops.