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Open Pillar Lagoon

#17b9df
Notes

Open Pillar Lagoon (#17B9DF) 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 (191°, 81%, 48%) 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
#17b9df
RGB
rgb(23, 185, 223)
HSL
hsl(191, 81%, 48%)
HWB
hwb(191 9% 13%)
OKLCH
oklch(72.8% 0.129 220.1)
P3
color(display-p3 0.3375 0.7148 0.8582)
HSV
hsv(191, 90%, 87%)
LAB
lab(69.61% -24.79 -29.74)
LCH
lch(69.61% 38.72 230.18)
CMYK
cmyk(90%, 17%, 0%, 13%)

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.

Pillar
modifier

Latin pīla, pillar. As a color modifier, pillar implies a vertical-load-bearing-and-monumental quality, the visual register of Roman-and-Greek-and-Egyptian-Pillar hand-cut Doric-and-Ionic-and-Corinthian-Egyptian column-and-pillar monumental-architecture surfaces under classical-pillar monumental-architecture light. Sits at the modifier-and-architecture end of the grid, parallel to column and plinth in usage.

Lagoon
noun

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.

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.

#17b9df
Original
#a2b4e1
Protanopia
#8aa2df
Deuteranopia
#00c5c5
Tritanopia
#999999
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
2.32:1
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
9.04:1

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
##17B9DF
Display P3
Display P3
color(display-p3 0.3375 0.7148 0.8582)
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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