Radiant Sulfur
Radiant Sulfur (#BFBC18) is a true yellow with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (59°, 78%, 42%) 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 blue. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
From the Latin radiare, to emit rays — used as a color word since the seventeenth century for hues that read as luminous and emitting. Radiant gold, radiant pink: the implication is high luminance combined with the optical impression of an outward light. Sits in the bright-bucket center alongside glowing.
Element S, atomic number 16 — bright yellow crystalline mineral around volcanic vents from Sicily to Hokkaidō. Pure sulfur dust gave its color to the explosive mixtures of medieval gunpowder and to the fungicide vineyards of nineteenth-century France. The color is the surface of a freshly cleaved sulfur crystal: a saturated, slightly green-shifted yellow with the resinous finish of the elemental mineral.
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.