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Frank Atoll

#056423
Notes

Frank Atoll (#056423) is a deep green with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (139°, 90%, 21%) places it in the highly saturated band at a dark 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 magenta. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#056423
RGB
rgb(5, 100, 35)
HSL
hsl(139, 90%, 21%)
HWB
hwb(139 2% 61%)
OKLCH
oklch(43.9% 0.127 147.2)
HSV
hsv(139, 95%, 39%)
LAB
lab(36.49% -39.89 29.31)
LCH
lch(36.49% 49.50 143.69)
CMYK
cmyk(95%, 0%, 65%, 61%)

Etymology

Frank
adjective

From the Old French franc, free, sincere — used as a color modifier since the seventeenth century for hues that read as direct and unhedged. Frank red, frank brown: moderate-to-high saturation combined with optical directness. Sits at the crisp-bucket alongside direct and honest.

Atoll
noun

A ring-shaped coral reef enclosing a central lagoon — the geological signature of subsiding volcanic islands ringed by upward-growing coral. Atoll color refers to the unifying blue-green of a Maldivian-style atoll lagoon seen from above: a saturated, slightly cool deep blue-green with the optical clarity of shallow tropical water.

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

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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.

#056423
Original
#655a1c
Protanopia
#5c5329
Deuteranopia
#006256
Tritanopia
#4b4b4b
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).
AAAon White
7.36:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon Black
2.85:1

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