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Refulgent Gown Turquoise

#21d9cf
Notes

Refulgent Gown Turquoise (#21D9CF) 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 (177°, 74%, 49%) 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
#21d9cf
RGB
rgb(33, 217, 207)
HSL
hsl(177, 74%, 49%)
HWB
hwb(177 13% 15%)
OKLCH
oklch(80.0% 0.134 188.8)
P3
color(display-p3 0.4040 0.8386 0.8087)
HSV
hsv(177, 85%, 85%)
LAB
lab(78.72% -44.21 -7.30)
LCH
lch(78.72% 44.80 189.38)
CMYK
cmyk(85%, 0%, 5%, 15%)

Etymology

Refulgent
adjective

Latin refulgēns, shining-back — present-participle of refulgere, sharing root with fulgor (lightning). As a color modifier, refulgent implies a saturated-and-reflective-shining quality, the bright color of polished-bronze-and-armor reflective-surface mid-day-sun reflection. Sits at the bright-and-saturated end of the grid, parallel to effulgent and resplendent in usage.

Gown
modifier

Old French goune, long-loose-garment. As a color modifier, gown implies a Tudor-and-Elizabethan-and-formal-evening-gown quality, the visual register of Tudor-and-Elizabethan-and-Worth-couture-gown hand-Tudor-and-Elizabethan-and-formal-evening-gown Tudor-and-Elizabethan-and-Worth-couture-gown-and-Belle-Époque gown-and-Tudor-and-Elizabethan surfaces under Tudor-and-Elizabethan-and-Worth-couture-gown-and-Belle-Époque Hampton-Court-and-Maison-Worth-Paris court-and-couture-light. Sits at the modifier-and-textile end of the grid, parallel to robe and frock 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.

#21d9cf
Original
#cccdcf
Protanopia
#b5bcd0
Deuteranopia
#00dfd6
Tritanopia
#b1b1b1
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
1.77:1
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
11.89:1

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
##21D9CF
Display P3
Display P3
color(display-p3 0.4040 0.8386 0.8087)
P3 has subtle headroomOKLCH chroma 0.134

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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