Sinister Atlantic
Sinister Atlantic (#123F99) is a deep azure with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (220°, 79%, 34%) places it in the highly saturated band at a dark 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Latin sinister, left / unlucky — used in classical-augury for the unfavorable left-hand-side of bird-flight omen-reading. As a color modifier, sinister implies a deep-and-foreboding-and-uncanny quality, the dark of Gothic-novel atmospheric-shadow and threatening-presence. Sits at the deep-and-uncanny end of the grid, parallel to foreboding and menacing in atmospheric register.
The body of saltwater between the Americas and Eurasia/Africa — second-largest of Earth's oceans by area, deeper colored by river silt than the Mediterranean. The color refers to the average reflectance of mid-North Atlantic water on a clear day: a saturated, slightly muted blue with the optical depth of cold open water. Deeper than mediterranean, cooler than peacock, with the geographic weight of an ocean named for Atlas at its western horizon.
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.