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Heavy Sleek Cerulean

#218cd6
Notes

Heavy Sleek Cerulean (#218CD6) 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 (205°, 73%, 48%) 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
#218cd6
RGB
rgb(33, 140, 214)
HSL
hsl(205, 73%, 48%)
HWB
hwb(205 13% 16%)
OKLCH
oklch(61.9% 0.144 245.2)
HSV
hsv(205, 85%, 84%)
LAB
lab(56.02% -2.79 -45.99)
LCH
lch(56.02% 46.07 266.53)
CMYK
cmyk(85%, 35%, 0%, 16%)

Etymology

Heavy
adjective

Old English hefig, weighty — cognate with heave. Used as a color modifier since at least the seventeenth century to indicate weight in saturation as much as value: heavy with pigment, heavy-bodied. In the engine's adjective grid, heavy sits alongside deep and plush in the dark-and-saturated quadrant. Closer to a fabric description than a pure value word.

Sleek
modifier

Middle Dutch sleeck, smooth. As a color modifier, sleek implies a smooth-and-streamlined quality, the visual register of Mid-Century-Modern-and-Streamline-Moderne-sleek hand-streamlined-and-aerodynamic-and-polished aluminum-and-chrome-and-bakelite Mid-Century-Modern-and-Streamline-Moderne sleek-and-streamlined surfaces under Mid-Century-Modern-and-Streamline-Moderne sleek-and-polished light. Sits at the modifier-and-texture end of the grid, parallel to gloss and shine 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.

#218cd6
Original
#698fd9
Protanopia
#4f7fd5
Deuteranopia
#009ea7
Tritanopia
#7b7b7b
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
3.63:1
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
5.79:1

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