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Shielded Unda Royal

#255dd9
Notes

Shielded Unda Royal (#255DD9) 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 (221°, 71%, 50%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#255dd9
RGB
rgb(37, 93, 217)
HSL
hsl(221, 71%, 50%)
HWB
hwb(221 15% 15%)
OKLCH
oklch(52.0% 0.199 263.0)
P3
color(display-p3 0.2049 0.3598 0.8210)
HSV
hsv(221, 83%, 85%)
LAB
lab(43.11% 28.03 -68.44)
LCH
lch(43.11% 73.95 292.27)
CMYK
cmyk(83%, 57%, 0%, 15%)

Etymology

Shielded
adjective

Old English scild, shield — past-participle of shield, sharing root with German Schild. As a color modifier, shielded implies a saturated-and-protected-and-defensive quality, the deep-rich color of medieval-knight armorial-shield-and-coat-of-arms heraldic display. Sits at the bold-and-fortified end of the grid, parallel to armored and bastioned.

Unda
modifier

Latin unda, wave-or-water. As a color modifier, unda implies a Latin-wave-and-water-and-Roman-aqueduct quality, the visual register of Roman-aqueduct-and-Pontine-marsh-unda hand-Latin-wave-and-water-and-Roman-aqueduct Roman-aqueduct-and-Pontine-marsh-unda-and-Tiber-flow unda-and-Latin-wave-and-water surfaces under Roman-aqueduct-and-Pontine-marsh-unda-and-Tiber-flow Aqua-Claudia-and-Aqua-Marcia Roman-water-light. Sits at the modifier-and-Latin end of the grid, parallel to via and arbor in usage.

Royal
noun

The blue of European royal court dress and regalia from the late seventeenth century forward — the color of British peers' robes, French royal sashes, the lining of the crown-jewel cases. The color refers to a saturated, slightly violet-shifted blue with the matte finish of velvet or melton wool dyed to maximum intensity: deeper than cornflower, warmer than ultramarine, with the heraldic weight of a color reserved for monarchs and the official Crown.

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.

#255dd9
Original
#006edd
Protanopia
#005ed7
Deuteranopia
#007c92
Tritanopia
#5a5a5a
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
5.76:1
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
3.65:1

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
##255DD9
Display P3
Display P3
color(display-p3 0.2049 0.3598 0.8210)
P3 has visible headroomOKLCH chroma 0.199

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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