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Imposing Domus Ultramarine

#0a3081
Notes

Imposing Domus Ultramarine (#0A3081) is a deep azure 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 (221°, 86%, 27%) places it in the highly saturated band at a dark lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. For a confident two-color system, pair it with its complementary amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#0a3081
RGB
rgb(10, 48, 129)
HSL
hsl(221, 86%, 27%)
HWB
hwb(221 4% 49%)
OKLCH
oklch(34.3% 0.143 262.6)
P3
color(display-p3 0.0842 0.1852 0.4869)
HSV
hsv(221, 92%, 51%)
LAB
lab(22.87% 21.57 -48.94)
LCH
lch(22.87% 53.48 293.79)
CMYK
cmyk(92%, 63%, 0%, 49%)

Etymology

Imposing
adjective

Latin impōnere, to place upon — present-participle of impose. As a color modifier, imposing implies a deep-and-massive-and-architectural quality, the dark cool-gray of Citadel-and-Cathedral monumental architecture against the sky. Sits at the deep-and-architectural end of the grid, parallel to towering and looming in scale.

Domus
modifier

Latin domus, house-or-home. As a color modifier, domus implies a Latin-house-and-Roman-domus-and-atrium quality, the visual register of Pompeian-domus-and-Roman-atrium hand-Latin-house-and-Roman-domus-and-atrium Pompeian-domus-and-Roman-atrium-and-impluvium domus-and-Latin-house surfaces under Pompeian-domus-and-Roman-atrium-and-impluvium Pompeian-and-Herculaneum-domus Roman-villa-light. Sits at the modifier-and-Latin end of the grid, parallel to arbor and via in usage.

Ultramarine
noun

The pigment ground from lapis lazuli — the Afghan mineral imported through Venice in the late Middle Ages, more expensive by weight than gold during the Renaissance. The color refers to a freshly mixed ultramarine pigment in linseed oil: a saturated, slightly violet-shifted deep blue with the matte finish of micron-ground rock. Deeper than cobalt, cooler than royal, with the art-historical weight of the blue Vermeer reserved for Mary's robe.

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.

#0a3081
Original
#003c84
Protanopia
#00317f
Deuteranopia
#004553
Tritanopia
#2e2e2e
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
11.98:1
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
1.75:1

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
##0A3081
Display P3
Display P3
color(display-p3 0.0842 0.1852 0.4869)
P3 has subtle headroomOKLCH chroma 0.143

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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