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Crisp Nun Fern

#66b454
Notes

Crisp Nun Fern (#66B454) 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 (109°, 39%, 52%) 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
#66b454
RGB
rgb(102, 180, 84)
HSL
hsl(109, 39%, 52%)
HWB
hwb(109 33% 29%)
OKLCH
oklch(69.8% 0.153 139.9)
P3
color(display-p3 0.4735 0.6984 0.3750)
HSV
hsv(109, 53%, 71%)
LAB
lab(66.60% -42.66 41.18)
LCH
lch(66.60% 59.29 136.02)
CMYK
cmyk(43%, 0%, 53%, 29%)

Etymology

Crisp
adjective

Latin crispus, curled — drifted in English from the curled hair sense to fresh and clean. As a color modifier, crisp implies saturation combined with optical clarity, with no haze or film between the eye and the surface. Used across the bright and crisp buckets where the hue is fresh-looking. Slightly less assertive than vivid.

Nun
modifier

Latin nonna, mother / nun. As a color modifier, nun implies a Carmelite-and-Benedictine-religious-sister quality, the visual register of Carmelite-and-Benedictine-Nun hand-spun robe-and-veil-and-wimple Carmelite-and-Benedictine-religious-sister surfaces under Carmelite-and-Benedictine-Religious-Sister hand-spun-robe-and-wimple convent-cloister light. Sits at the modifier-and-cultural end of the grid, parallel to monk and friar in usage.

Fern
noun

The Polypodiopsida — vascular spore-bearing plants that dominated terrestrial flora during the Carboniferous, when their compressed bodies became most of the world's coal. The color refers to the upper surface of a healthy mid-summer fern frond: a saturated, slightly muted green with the matte finish of mature pinnae. Deeper than moss, cooler than chartreuse, with the patient persistence of a plant family three hundred million years old.

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.

#66b454
Original
#b9a64b
Protanopia
#ae9f5b
Deuteranopia
#60af9e
Tritanopia
#9c9c9c
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
2.55:1
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
8.22:1

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
##66B454
Display P3
Display P3
color(display-p3 0.4735 0.6984 0.3750)
P3 has subtle headroomOKLCH chroma 0.153

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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