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Robust Gloaming

#643bb8
Notes

Robust Gloaming (#643BB8) 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 (260°, 51%, 48%) 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
#643bb8
RGB
rgb(100, 59, 184)
HSL
hsl(260, 51%, 48%)
HWB
hwb(260 23% 28%)
OKLCH
oklch(47.3% 0.186 293.0)
HSV
hsv(260, 68%, 72%)
LAB
lab(36.55% 46.48 -59.81)
LCH
lch(36.55% 75.74 307.85)
CMYK
cmyk(46%, 68%, 0%, 28%)

Etymology

Robust
adjective

From the Latin robustus, of oak — implying strength combined with substance. As a color modifier, robust describes saturation combined with body: a robust burgundy, a robust olive. Sits in the bold-and-warm corner alongside strong and solid, with the slightly textural implication of a color that has substance behind the pigment.

Gloaming
noun

Scots and Northern English gloming, twilight — derived from Old English glōmung, related to glōm (gloom) but specifically denoting the half-light between sunset and full dark. Gloaming color refers to a Highland-loch eastern sky at the gloaming: a saturated, slightly cool deep blue-violet with the optical complexity of Rayleigh-scattered atmospheric Belt of Venus light over a wet Scottish horizon.

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.

#643bb8
Original
#0058bc
Protanopia
#0054b5
Deuteranopia
#4b5a75
Tritanopia
#4d4d4d
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
7.34:1
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
2.86:1

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