Coruscating Sheet Sky
Coruscating Sheet Sky (#21ABF7) is a true azure with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (201°, 93%, 55%) places it in the highly saturated band at a mid lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. 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 coruscāns, flashing — present-participle of coruscāre. As a color modifier, coruscating implies a saturated-and-rapidly-flashing quality, the bright color of lightning-strike atmospheric-electrical-discharge against the night-sky. Sits at the bright-and-flashing end of the grid, parallel to flashing and flickering in usage.
Old English scēate, rope-attached-to-sail. As a color modifier, sheet implies a rope-attached-to-sail-corner quality, the visual register of Tall-Ship-and-yacht-sheet hand-tied rope-attached-to-sail-corner mainsheet-and-jibsheet maritime-rigging surfaces under tall-ship-sheet-and-mainsheet maritime-rigging light. Sits at the modifier-and-nautical end of the grid, parallel to knot and sail in usage.
The blue of a clear sky at noon — produced by Rayleigh scattering, the preferential dispersion of shorter wavelengths through atmospheric molecules. Air itself is colorless; the color we see is sunlight scattered toward our eyes by every cubic kilometer above. The reference shade is mid-latitude noon under a high pressure system: a clean, slightly green-shifted blue with the luminous depth of light scattered across an entire hemisphere of air.
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.