Clean Bluestar
Clean Bluestar (#91BDE4) is a soft azure 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 (208°, 61%, 73%) 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
Old English clǣne, pure, free of dirt — used as a color modifier since the medieval period for hues that read as crisp and uncontaminated by other pigments. Clean white, clean blue: moderate saturation combined with optical clarity. Sits at the crisp-bucket center alongside clear and true.
The genus Amsonia — bluestar, North American and East Asian native perennials with clusters of pale-blue star-shaped flowers in late spring. A. tabernaemontana and A. hubrichtii are signature pollinator-garden plants. The color refers to a fresh Amsonia flower cluster: a soft, slightly cool pale blue with the matte finish of small five-petaled stars.
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.