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Heavy Dux Tanzanite

#5a3788
Notes

Heavy Dux Tanzanite (#5A3788) is a true 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 (266°, 42%, 37%) 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 lime. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#5a3788
RGB
rgb(90, 55, 136)
HSL
hsl(266, 42%, 37%)
HWB
hwb(266 22% 47%)
OKLCH
oklch(42.0% 0.131 300.8)
P3
color(display-p3 0.3334 0.2219 0.5155)
HSV
hsv(266, 60%, 53%)
LAB
lab(31.08% 33.33 -39.73)
LCH
lch(31.08% 51.86 309.99)
CMYK
cmyk(34%, 60%, 0%, 47%)

Etymology

Heavy
adjective

Old English hefig, weighty — cognate with heave. Used as a color modifier since at least the seventeenth century to indicate weight in saturation as much as value: heavy with pigment, heavy-bodied. In the engine's adjective grid, heavy sits alongside deep and plush in the dark-and-saturated quadrant. Closer to a fabric description than a pure value word.

Dux
modifier

Latin dux, leader-or-general. As a color modifier, dux implies a Latin-leader-and-Roman-general-and-Doge quality, the visual register of Roman-dux-and-Venetian-Doge hand-Latin-leader-and-Roman-general-and-Doge Roman-dux-and-Venetian-Doge-and-Renaissance-condottiere dux-and-Latin-leader surfaces under Roman-dux-and-Venetian-Doge-and-Renaissance-condottiere Republican-Rome-and-Venetian-Doge's-Palace leader-and-general-light. Sits at the modifier-and-Latin end of the grid, parallel to pater and virtus in usage.

Tanzanite
noun

A blue-violet variety of zoisite — discovered in 1967 in a single small area of northern Tanzania near Mount Kilimanjaro and marketed by Tiffany & Co. shortly after. The color refers to a faceted tanzanite cut to maximize its strong pleochroism: a saturated, slightly violet-shifted deep blue-purple with the gem's signature internal life. Cooler than amethyst, warmer than iolite, with the gem-trade specificity of a stone that occurs in exactly one place on Earth.

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.

#5a3788
Original
#10498b
Protanopia
#204986
Deuteranopia
#51475a
Tritanopia
#444444
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
8.99:1
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
2.34:1

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
##5A3788
Display P3
Display P3
color(display-p3 0.3334 0.2219 0.5155)
P3 has subtle headroomOKLCH chroma 0.131

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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