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Brilliant Cyan

#42dffb
Notes

Brilliant Cyan (#42DFFB) is a true cyan with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (189°, 96%, 62%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#42dffb
RGB
rgb(66, 223, 251)
HSL
hsl(189, 96%, 62%)
HWB
hwb(189 26% 2%)
OKLCH
oklch(83.5% 0.131 212.5)
HSV
hsv(189, 74%, 98%)
LAB
lab(82.32% -31.12 -25.26)
LCH
lch(82.32% 40.08 219.06)
CMYK
cmyk(74%, 11%, 0%, 2%)

Etymology

Brilliant
adjective

From the Italian brillante, sparkling — used as a color modifier since the seventeenth century for hues that read as optically active beyond their literal saturation. Brilliant green, brilliant blue: the implication is luminance combined with the slight sparkle of a high-refractive surface. Sits at the bright-bucket center alongside vivid and bright.

Cyan
noun

From the Greek kyanos, deep blue, originally referring to the lapis-derived blue of antiquity. In modern usage, cyan is one of the four printing primaries (with magenta, yellow, and black) and an additive primary on screens. The color refers to a pure CMYK cyan tile: a saturated, clean blue-green with the optical brightness of an additive-color primary. Cooler than turquoise, lighter than cerulean, with the technical specificity of a color defined by a printing-press standard.

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.

#42dffb
Original
#cad7fd
Protanopia
#b0c5fb
Deuteranopia
#00eae8
Tritanopia
#c0c0c0
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
1.59:1
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
13.18:1

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