Open Sunup Mint
Open Sunup Mint (#9DE5B8) is a soft green 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 (143°, 58%, 76%) 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 magenta. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
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.
English compound sun + up, sun-up. As a color modifier, sunup implies a first-light-and-eastern-horizon quality, the visual register of clear-sky eastern-horizon sunrise-and-first-light Rayleigh-scattered atmospheric Belt-of-Venus pink-and-orange surfaces under sunrise eastern-horizon light. Sits at the modifier-and-time end of the grid, parallel to rise and wake in usage.
The genus Mentha — peppermint, spearmint, apple mint, water mint — the cooling herb whose menthol gives it that quality at the molecular level. The color refers to fresh peppermint leaves before drying: a clean, slightly cool green with the matte finish of trichome-rich leaf surface. Lighter than basil, cooler than parsley, with the mojito-and-Pimm's association of a herb tied to summer drinks across two continents.
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.
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.