Healthful Observatory
Healthful Observatory (#81A3E7) 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 (220°, 68%, 71%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old English hǣlth, health — adjectival suffix -ful. As a color modifier, healthful implies a clear-and-vital-and-wholesome quality where the hue carries the visual register of fresh-air-and-sunlight outdoor health-promoting environment. Sits at the crisp-and-wholesome end of the grid, parallel to salubrious and wholesome in usage.
An astronomical research facility — particularly the deep-blue interior paint of optical observatories like Mount Wilson, Palomar, and Mauna Kea. The deep blue minimizes stray-light reflection inside the dome. The color refers to the painted interior of a research-grade optical observatory: a saturated, slightly cool very deep blue with the matte finish of low-reflectance enamel.
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.