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Indomitable Roman Indigo

#0540a2
Notes

Indomitable Roman Indigo (#0540A2) 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 (217°, 94%, 33%) 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
#0540a2
RGB
rgb(5, 64, 162)
HSL
hsl(217, 94%, 33%)
HWB
hwb(217 2% 36%)
OKLCH
oklch(40.6% 0.168 260.9)
P3
color(display-p3 0.1021 0.2468 0.6120)
HSV
hsv(217, 97%, 64%)
LAB
lab(30.17% 23.83 -57.33)
LCH
lch(30.17% 62.08 292.57)
CMYK
cmyk(97%, 60%, 0%, 36%)

Etymology

Indomitable
adjective

Latin indomitābilis, unconquerable — derived from domāre (to tame). As a color modifier, indomitable implies a saturated-and-unconquerable-and-fierce quality where the hue resists any attempt to subdue or modulate its presence. Sits at the bold-and-resilient end of the grid, parallel to unyielding and adamant.

Roman
modifier

Latin Romanus, of-Rome. As a color modifier, roman implies an empire-built-and-classical quality, the visual register of Roman-Imperial hand-laid pavement-and-fresco-and-bronze-and-marble Republican-Imperial classical surfaces under Mediterranean-Roman-Imperial classical-architecture afternoon light. Sits at the modifier-and-cultural end of the grid, parallel to etruscan and hellenic in usage.

Indigo
noun

Indigofera tinctoria, the South Asian legume whose leaves yield the deep blue dye that has clothed humanity for at least four thousand years — Egyptian linen, Mayan textile, the slave-grown plantations of Carolina. The color refers to a freshly indigo-dyed cotton thread: a saturated, slightly violet-shifted deep blue with the slight lustre of a fiber surface oxidized in air. Deeper than cobalt, cooler than royal.

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.

#0540a2
Original
#004ea5
Protanopia
#0040a0
Deuteranopia
#00596a
Tritanopia
#3b3b3b
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
9.29:1
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
2.26:1

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
##0540A2
Display P3
Display P3
color(display-p3 0.1021 0.2468 0.6120)
P3 has subtle headroomOKLCH chroma 0.168

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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