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Honest Cerulean

#40b2e5
Notes

Honest Cerulean (#40B2E5) is a true cyan with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (199°, 76%, 57%) 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
#40b2e5
RGB
rgb(64, 178, 229)
HSL
hsl(199, 76%, 57%)
HWB
hwb(199 25% 10%)
OKLCH
oklch(72.1% 0.124 231.7)
HSV
hsv(199, 72%, 90%)
LAB
lab(68.45% -15.55 -34.77)
LCH
lch(68.45% 38.09 245.91)
CMYK
cmyk(72%, 22%, 0%, 10%)

Etymology

Honest
adjective

Latin honestus, honorable — used as a color modifier since the seventeenth century for hues that read as straightforward and unembellished, the working browns and grays of vernacular architecture rather than the polished shades of court fashion. Honest brown, honest gray: moderate saturation combined with optical directness. Sits at the crisp-bucket alongside plain and frank.

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.

#40b2e5
Original
#98b0e7
Protanopia
#82a0e4
Deuteranopia
#00c0c3
Tritanopia
#9d9d9d
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).
Failon White
2.41:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
8.72:1

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