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Flashing Tributary

#42e3f9
Notes

Flashing Tributary (#42E3F9) 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 (187°, 94%, 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
#42e3f9
RGB
rgb(66, 227, 249)
HSL
hsl(187, 94%, 62%)
HWB
hwb(187 26% 2%)
OKLCH
oklch(84.4% 0.131 208.6)
HSV
hsv(187, 73%, 98%)
LAB
lab(83.41% -33.63 -22.55)
LCH
lch(83.41% 40.49 213.85)
CMYK
cmyk(73%, 9%, 0%, 2%)

Etymology

Flashing
adjective

Old English flasch, flash — present-participle of flash. As a color modifier, flashing implies a saturated-and-rapid-on-off quality, the bright color of emergency-vehicle and photographic-flash light-burst surfaces. Sits at the bright-and-flashing end of the grid, parallel to coruscating and flickering in usage.

Tributary
noun

A smaller river that flows into a larger one — the Ohio is a tributary of the Mississippi, the Vltava of the Elbe. Tributary color refers to a clear-water tributary as it joins a sediment-laden main river: a soft, slightly cool deep blue-green with the optical complexity of unmixed clear-and-silty water boundary.

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.

#42e3f9
Original
#cfdafa
Protanopia
#b6c8f9
Deuteranopia
#00edea
Tritanopia
#c2c2c2
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
1.55:1
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
13.59:1

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