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Open Quell Ocean

#42e3df
Notes

Open Quell Ocean (#42E3DF) 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 (179°, 74%, 57%) 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
#42e3df
RGB
rgb(66, 227, 223)
HSL
hsl(179, 74%, 57%)
HWB
hwb(179 26% 11%)
OKLCH
oklch(83.5% 0.129 192.5)
P3
color(display-p3 0.4628 0.8779 0.8695)
HSV
hsv(179, 71%, 89%)
LAB
lab(82.60% -41.09 -10.00)
LCH
lch(82.60% 42.29 193.68)
CMYK
cmyk(71%, 0%, 2%, 11%)

Etymology

Open
adjective

Old English open, unobstructed — used as a color modifier since the eighteenth century for hues that read as airy or uncrowded. Open blue, open green: moderate saturation combined with optical spaciousness, the slight visual breath of a hue that doesn't crowd the surface it covers. Sits at the crisp-bucket center alongside clear.

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.

Ocean
noun

The body of saltwater that covers seventy percent of Earth's surface — a single connected mass divided by convention into Atlantic, Pacific, Indian, Southern, and Arctic. The color refers to the average reflectance of mid-depth temperate ocean: a saturated, slightly green-shifted deep blue with the optical depth of a body of water that absorbs all light below the photic zone. Deeper than mediterranean, cooler than peacock.

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.

#42e3df
Original
#d5d8df
Protanopia
#bec6e0
Deuteranopia
#00eae1
Tritanopia
#c0c0c0
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
1.58:1
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
13.28:1

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
##42E3DF
Display P3
Display P3
color(display-p3 0.4628 0.8779 0.8695)
P3 has subtle headroomOKLCH chroma 0.129

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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