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Effulgent Skullcap

#289ae4
Notes

Effulgent Skullcap (#289AE4) 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 (204°, 78%, 53%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#289ae4
RGB
rgb(40, 154, 228)
HSL
hsl(204, 78%, 53%)
HWB
hwb(204 16% 11%)
OKLCH
oklch(66.0% 0.147 243.3)
P3
color(display-p3 0.3032 0.5953 0.8704)
HSV
hsv(204, 82%, 89%)
LAB
lab(60.92% -5.22 -46.04)
LCH
lch(60.92% 46.33 263.54)
CMYK
cmyk(82%, 32%, 0%, 11%)

Etymology

Effulgent
adjective

Latin effulgēns, shining-out — present-participle of effulgere, sharing root with fulgor (lightning). As a color modifier, effulgent implies a saturated-and-radiating-light-out quality, the bright color of Renaissance-Madonna halo-and-aureole gold-leaf-and-pigment emission. Sits at the bright-and-saturated end of the grid, parallel to resplendent and radiant in usage.

Skullcap
noun

The genus Scutellariaskullcap, mint-family perennials whose helmet-shaped blue flowers and herbal medicinal properties have been used in Chinese, North American, and European traditional medicine. The color refers to a fresh S. baicalensis bloom: a saturated, slightly cool deep blue-violet with the matte finish of bilateral bracted flower.

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.

#289ae4
Original
#779ce7
Protanopia
#5d8be3
Deuteranopia
#00acb5
Tritanopia
#878787
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).
AA Largeon White
3.07:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
6.83:1

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
##289AE4
Display P3
Display P3
color(display-p3 0.3032 0.5953 0.8704)
P3 has subtle headroomOKLCH chroma 0.147

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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