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Pleasant Senex Lagoon

#42b5d4
Notes

Pleasant Senex Lagoon (#42B5D4) 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 (193°, 63%, 55%) 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
#42b5d4
RGB
rgb(66, 181, 212)
HSL
hsl(193, 63%, 55%)
HWB
hwb(193 26% 17%)
OKLCH
oklch(72.1% 0.110 219.3)
P3
color(display-p3 0.3913 0.7004 0.8175)
HSV
hsv(193, 69%, 83%)
LAB
lab(68.72% -22.30 -25.04)
LCH
lch(68.72% 33.53 228.31)
CMYK
cmyk(69%, 15%, 0%, 17%)

Etymology

Pleasant
adjective

From the French plaisant, pleasing — used as a color modifier since the fifteenth century for hues that read as agreeable, the kind of color that wears well over a long viewing without becoming demanding or fatiguing. Pleasant green, pleasant rose: moderate saturation combined with optical comfort. Sits at the crisp-bucket alongside easy and calm.

Senex
modifier

Latin senex, old-man-or-elder. As a color modifier, senex implies a Latin-elder-and-Roman-Senate-elder quality, the visual register of Cicero-Cato-the-Elder-senex hand-Latin-elder-and-Roman-Senate-elder Cicero-Cato-the-Elder-senex-and-De-Senectute senex-and-Latin-elder-and-Roman-Senate-elder surfaces under Cicero-Cato-the-Elder-senex-and-De-Senectute Roman-Senate-and-villa-retreat venerable-elder-light. Sits at the modifier-and-Latin end of the grid, parallel to pater and virtus 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.

#42b5d4
Original
#a2b0d6
Protanopia
#8da1d4
Deuteranopia
#00bfbf
Tritanopia
#9f9f9f
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
2.39:1
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
8.79:1

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
##42B5D4
Display P3
Display P3
color(display-p3 0.3913 0.7004 0.8175)
P3 has subtle headroomOKLCH chroma 0.110

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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