Aqueous Surf
Aqueous Surf (#B9D1DB) is a soft cyan with a pastel character. It reads calm and airy, with enough chroma to feel intentional rather than washed out. Its HSL profile (198°, 32%, 79%) places it in the balanced band at a light lightness. It works as a background wash, large-area fill, or soft illustration tone. Add a darker ink of the same hue when you need type over it. For a confident two-color system, pair it with its complementary orange. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Latin aquōsus, full of water — adjectival suffix -ous. As a color modifier, aqueous implies a pale-and-water-thin-and-translucent quality, the pale color of Japanese-sumi-e and Chinese-Song-dynasty-painting heavy-water-dilution ink-painting surface-finish. Sits at the pale-and-diluted end of the grid, parallel to watery and thinned in usage.
The white water produced where waves break — bubbles of compressed air carried in shallow water and dispersing as the wave reforms. The color refers to surf retreating across wet sand: a soft, very pale blue-green with the optical brightness of bubble dispersion. Lighter than seafoam, cooler than frost, with the kinetic weight of a color that's never still — every photograph of surf is already obsolete.
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 exploreHarmonies
Accessibility
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.
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.
Wide gamut
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.
This color sits well within the sRGB cube. P3 and sRGB share the gray axis and most desaturated tones, so a P3 display renders this identically to an sRGB display.