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Useful Procyon Lagoon

#30b5d1
Notes

Useful Procyon Lagoon (#30B5D1) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (190°, 64%, 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
#30b5d1
RGB
rgb(48, 181, 209)
HSL
hsl(190, 64%, 50%)
HWB
hwb(190 19% 18%)
OKLCH
oklch(71.6% 0.116 215.7)
P3
color(display-p3 0.3597 0.6998 0.8063)
HSV
hsv(190, 77%, 82%)
LAB
lab(68.22% -25.47 -24.18)
LCH
lch(68.22% 35.12 223.51)
CMYK
cmyk(77%, 13%, 0%, 18%)

Etymology

Useful
adjective

Latin ūsus, use — adjectival suffix -ful. As a color modifier, useful implies a clear-and-purpose-serving quality where the hue carries the visual register of helpful-and-supporting design-element. Sits at the crisp-and-functional end of the grid, parallel to practical and serviceable in usage.

Procyon
modifier

Greek προκύων, before-the-dog. As a color modifier, procyon implies a Canis-Minor-and-bright-foretaste-of-Sirius quality, the visual register of Canis-Minor-Procyon-and-Winter-Triangle hand-Canis-Minor-and-bright-foretaste-of-Sirius Canis-Minor-Procyon-and-Winter-Triangle-and-Bortle-1-sky procyon-and-Canis-Minor-and-bright-foretaste surfaces under Canis-Minor-Procyon-and-Winter-Triangle-and-Bortle-1-sky January-and-February-winter-zenith winter-stellar-light. Sits at the modifier-and-cosmic end of the grid, parallel to rigel and altair 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.

#30b5d1
Original
#a2afd3
Protanopia
#8ca0d1
Deuteranopia
#00bfbe
Tritanopia
#9b9b9b
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
2.43:1
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
8.66:1

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
##30B5D1
Display P3
Display P3
color(display-p3 0.3597 0.6998 0.8063)
P3 has subtle headroomOKLCH chroma 0.116

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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