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Cavernous Swamphen

#3f277b
Notes

Cavernous Swamphen (#3F277B) is a deep indigo with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (257°, 52%, 32%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary lime. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3f277b
RGB
rgb(63, 39, 123)
HSL
hsl(257, 52%, 32%)
HWB
hwb(257 15% 52%)
OKLCH
oklch(35.4% 0.135 291.0)
HSV
hsv(257, 68%, 48%)
LAB
lab(23.46% 32.78 -44.03)
LCH
lch(23.46% 54.89 306.66)
CMYK
cmyk(49%, 68%, 0%, 52%)

Etymology

Cavernous
adjective

An adjectival form of cavern, used principally for the deep darkness of large enclosed spaces. As a color modifier, cavernous implies the slightly cool deep blacks of a Lascaux-style cave or a basilica crypt — darkness with the optical complexity of a space larger than any single light source can fill. Sits in the deep-and-spatial end of the grid.

Swamphen
noun

Australasian Porphyrio melanotus — a large Rallidae shorebird with dark blue-violet plumage and a brilliant red beak-and-frontal-shield. Swamphen color refers to a Porphyrio melanotus in profile in a Murray-Darling wetland: a saturated, slightly cool deep blue-violet with the iridescent satin finish of structurally colored feather barbs. Closely related to the Pukeko of New Zealand and the Purple Gallinule of the Americas.

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.

#3f277b
Original
#00397e
Protanopia
#003679
Deuteranopia
#2c3b4d
Tritanopia
#323232
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
11.75:1
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
1.79:1

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