Acid Larkspur
Acid Larkspur (#509DE6) is a true azure with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (209°, 75%, 61%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Latin acidus, sour — sharing root with English acrid and acerbic. As a color modifier, acid implies a saturated-and-citric-and-zingy quality, the bright color of lemon-and-lime citrus-fruit-flesh and acid-yellow fluorescent-pigment surfaces. Sits at the bright-and-cool end of the grid, parallel to acidic and electric in usage.
Delphinium consolida and its garden cousins — the tall spired wildflower of European meadows whose name means little lark for the spurred shape of its blossoms. The color refers to a fresh larkspur stalk in cottage-garden bloom: a saturated, slightly violet-shifted blue with the matte finish of multi-petaled flowers stacked along a single stem. Cooler than cornflower, warmer than periwinkle, with the literary weight of a flower in Tennyson and Heaney alike.
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.