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Bastioned Taurus Cerulean

#3990e1
Notes

Bastioned Taurus Cerulean (#3990E1) 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 (209°, 74%, 55%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3990e1
RGB
rgb(57, 144, 225)
HSL
hsl(209, 74%, 55%)
HWB
hwb(209 22% 12%)
OKLCH
oklch(64.0% 0.147 250.0)
P3
color(display-p3 0.3193 0.5573 0.8578)
HSV
hsv(209, 75%, 88%)
LAB
lab(58.27% 1.26 -48.54)
LCH
lch(58.27% 48.55 271.49)
CMYK
cmyk(75%, 36%, 0%, 12%)

Etymology

Bastioned
adjective

Italian bastionato, fortified-with-bastions — past-participle of bastion, derived from bastia (fortified-tower). As a color modifier, bastioned implies a saturated-and-fortified-and-projecting quality, the deep-rich color of Vauban-period military-fortress star-fort projecting-bastion stone-architecture. Sits at the bold-and-fortified end of the grid, parallel to fortified and buttressed.

Taurus
modifier

Latin taurus, bull-of-the-zodiac. As a color modifier, taurus implies a bull-and-earth-sign-and-Venus-ruled-fixed-earth quality, the visual register of Mesopotamian-bull-and-Greek-Taurus hand-bull-and-earth-sign-and-Venus-ruled-fixed-earth Mesopotamian-bull-and-Greek-Taurus-and-Pleiades-cluster taurus-and-bull-and-earth-sign surfaces under Mesopotamian-bull-and-Greek-Taurus-and-Pleiades-cluster spring-and-April-and-May fixed-earth-sign-light. Sits at the modifier-and-zodiac end of the grid, parallel to aries and gemini in usage.

Cerulean
noun

From the Latin caeruleum, originally referring to dark blue paint pigment of the Roman world, then via French céruléen into English. As a modern art-supply name, cerulean blue is the cobalt-tin oxide pigment introduced in 1805. The color refers to a clean, slightly green-shifted blue with the matte finish of mineral pigment in linseed oil: lighter than cobalt, deeper than aqua, with the painter's weight of a word for sky.

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.

#3990e1
Original
#6a95e4
Protanopia
#5285df
Deuteranopia
#00a3ae
Tritanopia
#838383
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
3.36:1
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
6.25:1

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
##3990E1
Display P3
Display P3
color(display-p3 0.3193 0.5573 0.8578)
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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