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Praetorian Vega Indigo

#0551d9
Notes

Praetorian Vega Indigo (#0551D9) is a true azure with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (218°, 95%, 44%) places it in the highly saturated band at a mid 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
#0551d9
RGB
rgb(5, 81, 217)
HSL
hsl(218, 95%, 44%)
HWB
hwb(218 2% 15%)
OKLCH
oklch(49.1% 0.218 261.8)
P3
color(display-p3 0.1326 0.3125 0.8197)
HSV
hsv(218, 98%, 85%)
LAB
lab(39.45% 34.29 -74.44)
LCH
lch(39.45% 81.96 294.74)
CMYK
cmyk(98%, 63%, 0%, 15%)

Etymology

Praetorian
adjective

Latin praetōriānus, of the praetor — adjectival suffix, referring to the Roman-Imperial elite guard-cohorts. As a color modifier, praetorian implies a saturated-and-elite-and-imperial-guard quality, the deep-rich color of Roman-Praetorian-Guard elite-imperial-bodyguard scarlet-tunic-and-bronze-armor military-formation. Sits at the bold-and-formal end of the grid, parallel to spartan and imperial.

Vega
modifier

Arabic al-nasr-al-wāqi', the-falling-eagle. As a color modifier, vega implies a brilliant-blue-white-and-summer-zenith quality, the visual register of Lyra-constellation-and-northern-summer-Vega hand-brilliant-blue-white-and-summer-zenith Lyra-constellation-and-northern-summer-and-Bortle-1-sky vega-and-brilliant-blue-white-and-summer-zenith surfaces under Lyra-constellation-and-northern-summer-and-Bortle-1-sky July-and-August-northern-zenith deep-sky-light. Sits at the modifier-and-cosmic end of the grid, parallel to deneb and altair 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.

#0551d9
Original
#0066dd
Protanopia
#0054d6
Deuteranopia
#00758d
Tritanopia
#4b4b4b
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).
AAon White
6.59:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon Black
3.19:1

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
##0551D9
Display P3
Display P3
color(display-p3 0.1326 0.3125 0.8197)
P3 has visible headroomOKLCH chroma 0.218

This color is chromatic enough that authoring it as P3 native (instead of clamping to sRGB) gives a perceptibly more saturated render on wide-gamut displays — modern Macs, iPhones, iPads, and most recent OLED laptops.

Related Colors

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