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Plutonian Madras

#3b1a88
Notes

Plutonian Madras (#3B1A88) is a deep indigo 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 (258°, 68%, 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
#3b1a88
RGB
rgb(59, 26, 136)
HSL
hsl(258, 68%, 32%)
HWB
hwb(258 10% 47%)
OKLCH
oklch(34.5% 0.166 287.8)
P3
color(display-p3 0.2145 0.1088 0.5124)
HSV
hsv(258, 81%, 53%)
LAB
lab(21.75% 42.97 -55.06)
LCH
lch(21.75% 69.85 307.97)
CMYK
cmyk(57%, 81%, 0%, 47%)

Etymology

Plutonian
adjective

From Pluto, the Roman god of the underworld (Greek Plouton). As a color modifier, plutonian implies the cool deep darkness of the underworld realms, with literary-classical register. Sits at the deep-and-cool end of the grid, parallel to Hadean and cooler than infernal.

Madras
noun

Indian Coromandel Coast city (now Chennai) — once the British East India Company's premier indigo export depot, processing Bihar and Bengal Indigofera tinctoria before shipment to Europe. Madras color refers to a Madras-checked indigo-and-white cotton handloom: a saturated, slightly cool deep blue-violet with the matte finish of multi-bath fermentation indigo on hand-loomed Coromandel cotton.

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.

#3b1a88
Original
#00378b
Protanopia
#003186
Deuteranopia
#1a3a51
Tritanopia
#292929
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
12.43:1
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
1.69:1

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
##3B1A88
Display P3
Display P3
color(display-p3 0.2145 0.1088 0.5124)
P3 has subtle headroomOKLCH chroma 0.166

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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