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Sinister Heraldry

#373c83
Notes

Sinister Heraldry (#373C83) is a true blue 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 (236°, 41%, 36%) 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 yellow. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#373c83
RGB
rgb(55, 60, 131)
HSL
hsl(236, 41%, 36%)
HWB
hwb(236 22% 49%)
OKLCH
oklch(39.2% 0.117 276.5)
P3
color(display-p3 0.2193 0.2347 0.4962)
HSV
hsv(236, 58%, 51%)
LAB
lab(28.60% 20.18 -40.79)
LCH
lch(28.60% 45.51 296.33)
CMYK
cmyk(58%, 54%, 0%, 49%)

Etymology

Sinister
adjective

Latin sinister, left / unlucky — used in classical-augury for the unfavorable left-hand-side of bird-flight omen-reading. As a color modifier, sinister implies a deep-and-foreboding-and-uncanny quality, the dark of Gothic-novel atmospheric-shadow and threatening-presence. Sits at the deep-and-uncanny end of the grid, parallel to foreboding and menacing in atmospheric register.

Heraldry
noun

Old French heraudie, herald-craft — the medieval European armorial-bearings system, where the heraldic tincture purpure (one of the rare stains) is rendered as a deep blue-violet on shields-and-banners since the 13th century. Heraldry color refers to a 14th-century French armorial-roll purpure tincture: a saturated, slightly cool deep blue-violet with the matte finish of vermilion-and-azurite-mixed armorial pigment.

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.

#373c83
Original
#144785
Protanopia
#044082
Deuteranopia
#0d4c59
Tritanopia
#404040
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
9.83:1
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
2.14:1

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
##373C83
Display P3
Display P3
color(display-p3 0.2193 0.2347 0.4962)
P3 has subtle headroomOKLCH chroma 0.117

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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