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Spectral Tropics

#21f5cf
Notes

Spectral Tropics (#21F5CF) is a true teal 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 (169°, 91%, 55%) 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
#21f5cf
RGB
rgb(33, 245, 207)
HSL
hsl(169, 91%, 55%)
HWB
hwb(169 13% 4%)
OKLCH
oklch(86.8% 0.159 175.6)
P3
color(display-p3 0.4549 0.9468 0.8178)
HSV
hsv(169, 87%, 96%)
LAB
lab(87.06% -55.87 4.90)
LCH
lch(87.06% 56.08 174.98)
CMYK
cmyk(87%, 0%, 16%, 4%)

Etymology

Spectral
adjective

Latin spectrum, appearance — adjectival suffix -al. As a color modifier, spectral implies a saturated-and-rainbow-decomposed-and-pure quality, the bright color of Newton-prism sunlight-decomposed seven-color spectrum band. Sits at the bright-and-pure end of the grid, parallel to prismatic and pure in usage.

Tropics
noun

The Earth's equatorial belt between the Tropic of Cancer and the Tropic of Capricorn — the region of the world where the sun reaches direct overhead at some point of the year. Tropics refers to the unifying blue-green of tropical-zone ocean and lagoon water: a saturated, slightly cool deep blue-green.

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.

#21f5cf
Original
#ece5cd
Protanopia
#d3d2d2
Deuteranopia
#00f8ea
Tritanopia
#c5c5c5
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
1.40:1
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
15.03:1

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
##21F5CF
Display P3
Display P3
color(display-p3 0.4549 0.9468 0.8178)
P3 has subtle headroomOKLCH chroma 0.159

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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