colors
Back to gallery

Pulsing Quell Turquoise

#21d6cf
Notes

Pulsing Quell Turquoise (#21D6CF) 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 (178°, 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#21d6cf
RGB
rgb(33, 214, 207)
HSL
hsl(178, 73%, 48%)
HWB
hwb(178 13% 16%)
OKLCH
oklch(79.3% 0.132 190.5)
P3
color(display-p3 0.3986 0.8270 0.8078)
HSV
hsv(178, 85%, 84%)
LAB
lab(77.83% -42.89 -8.63)
LCH
lch(77.83% 43.75 191.38)
CMYK
cmyk(85%, 0%, 3%, 16%)

Etymology

Pulsing
adjective

The progressive participle of pulse, to throb. Used as a color modifier for hues that read as if they were alternating between two states of luminance — the vibration of a high-saturation color against a contrasting background. Sits in the bright-bucket center alongside electric, with the implication of optical motion rather than static luminance.

Quell
modifier

Old English cwellan, to-kill-or-suppress. As a color modifier, quell implies a stilled-and-suppressed-and-pacified quality, the visual register of vesper-bell-and-curfew-quell hand-stilled-and-pacified-and-suppressed vesper-bell-and-curfew-bell-and-night-watch quelled-and-stilled-and-suppressed surfaces under vesper-bell-and-curfew-bell-and-night-watch hush-and-stillness-and-quiet bell-tower-and-monastery light. Sits at the modifier-and-mood end of the grid, parallel to hush and lull in usage.

Turquoise
noun

The hydrated copper-aluminum phosphate mined in Persia and the American Southwest for thousands of years — the firuze of Iran, the chalchihuitl of Mesoamerica, the heart of Pueblo and Navajo silverwork. The color refers to a fine Sleeping Beauty turquoise from Arizona: a saturated, slightly green-shifted blue with the slight matrix of host-rock veining. Brighter than persian, lighter than cerulean.

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.

#21d6cf
Original
#c9cacf
Protanopia
#b1b9d0
Deuteranopia
#00dcd3
Tritanopia
#afafaf
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
1.81:1
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
11.58:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##21D6CF
Display P3
Display P3
color(display-p3 0.3986 0.8270 0.8078)
P3 has subtle headroomOKLCH chroma 0.132

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

Related Colors

Canvas