Sullen Cyan
Sullen Cyan (#071728) 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 (211°, 70%, 9%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. 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 French solain, solitary via Anglo-French solein. As a color modifier, sullen implies a deep-and-cool-and-withholding quality, the dark cool-gray of Norwegian-fjord mid-winter atmospheric-overcast and saturated-saltwater-cliff in late-November light. Sits at the deep-and-cool end of the grid, parallel to gloomy and saturnine in atmospheric tone.
From the Greek kyanos, deep blue, originally referring to the lapis-derived blue of antiquity. In modern usage, cyan is one of the four printing primaries (with magenta, yellow, and black) and an additive primary on screens. The color refers to a pure CMYK cyan tile: a saturated, clean blue-green with the optical brightness of an additive-color primary. Cooler than turquoise, lighter than cerulean, with the technical specificity of a color defined by a printing-press standard.
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.