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Acid Coy Turquoise

#21ddcc
Notes

Acid Coy Turquoise (#21DDCC) 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 (175°, 74%, 50%) 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
#21ddcc
RGB
rgb(33, 221, 204)
HSL
hsl(175, 74%, 50%)
HWB
hwb(175 13% 13%)
OKLCH
oklch(80.9% 0.138 184.9)
P3
color(display-p3 0.4112 0.8541 0.7992)
HSV
hsv(175, 85%, 87%)
LAB
lab(79.84% -46.77 -4.05)
LCH
lch(79.84% 46.94 184.95)
CMYK
cmyk(85%, 0%, 8%, 13%)

Etymology

Acid
adjective

Latin acidus, sour — sharing root with English acrid and acerbic. As a color modifier, acid implies a saturated-and-citric-and-zingy quality, the bright color of lemon-and-lime citrus-fruit-flesh and acid-yellow fluorescent-pigment surfaces. Sits at the bright-and-cool end of the grid, parallel to acidic and electric in usage.

Coy
modifier

Latin quietus, still-and-quiet. As a color modifier, coy implies a shy-and-reserved-and-half-glanced quality, the visual register of Watteau-fête-galante-and-Rococo-coy hand-shy-and-reserved-and-half-glanced Watteau-fête-galante-and-Rococo-and-French-pastoral coyed-and-shy-and-reserved-and-half-glanced surfaces under Watteau-fête-galante-and-Rococo-and-French-pastoral garden-pavilion-and-fan-and-mask powdered-pastel-light. Sits at the modifier-and-mood end of the grid, parallel to meek and charm 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.

#21ddcc
Original
#d1d0cb
Protanopia
#babfce
Deuteranopia
#00e2d8
Tritanopia
#b4b4b4
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
1.71:1
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
12.28:1

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
##21DDCC
Display P3
Display P3
color(display-p3 0.4112 0.8541 0.7992)
P3 has subtle headroomOKLCH chroma 0.138

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.

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