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Stimulating Hydrangea

#15e4f4
Notes

Stimulating Hydrangea (#15E4F4) 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 (184°, 91%, 52%) 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
#15e4f4
RGB
rgb(21, 228, 244)
HSL
hsl(184, 91%, 52%)
HWB
hwb(184 8% 4%)
OKLCH
oklch(83.9% 0.141 204.0)
HSV
hsv(184, 91%, 96%)
LAB
lab(83.00% -38.86 -20.57)
LCH
lch(83.00% 43.97 207.89)
CMYK
cmyk(91%, 7%, 0%, 4%)

Etymology

Stimulating
adjective

Latin stimulāns, spurring on — present-participle of stimulate, derived from stimulus (a goad). As a color modifier, stimulating implies a saturated-and-arousing-and-attentive quality where the hue increases visual-and-cognitive engagement. Sits at the bright-and-active end of the grid, parallel to invigorating and bracing in usage.

Hydrangea
noun

The genus Hydrangea — particularly H. macrophylla, whose flower color depends on soil pH (acidic = blue, alkaline = pink). The color refers to a blue-bloom H. macrophylla in acidic-soil garden: a saturated, slightly cool deep blue-violet with the matte finish of clustered four-petaled florets.

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.

#15e4f4
Original
#d0daf5
Protanopia
#b5c6f5
Deuteranopia
#00eee9
Tritanopia
#b9b9b9
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
1.56:1
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
13.44:1

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