Fluorescent Plasma Goldenrod
Fluorescent Plasma Goldenrod (#B9CB11) 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 (66°, 85%, 43%) 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
Latin fluēre, to flow — adjectival suffix -escent. As a color modifier, fluorescent implies a saturated-and-UV-stimulated-glow quality, the bright color of fluorite-and-ZnS mineral-pigment fluorescent-lamp emission. Sits at the bright-and-cool end of the grid, parallel to phosphorescent and neon in usage.
Greek πλάσμα, something-molded-or-formed. As a color modifier, plasma implies an ionized-and-fourth-state-and-stellar-glow quality, the visual register of solar-corona-and-fluorescent-plasma hand-ionized-and-fourth-state-and-stellar-glow solar-corona-and-fluorescent-and-neon-tube plasma-and-ionized-and-fourth-state surfaces under solar-corona-and-fluorescent-and-neon-tube laboratory-and-stellar-and-aurora ionized-glow-light. Sits at the modifier-and-cosmic end of the grid, parallel to corona and nova in usage.
Solidago, the late-summer wildflower of North American meadows whose tall sprays of small yellow flowers signal the end of the growing season. The color refers to the flower head at full bloom: a warm, slightly muted yellow-orange with the matte finish of small clustered florets. Cooler than mustard, deeper than dandelion. The state flower of Kentucky and Nebraska, a pollinator magnet, and the original native dye for early American homespun.
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 is chromatic enough that authoring it as P3 native (instead of clamping to sRGB) gives a perceptibly more saturated render on wide-gamut displays — modern Macs, iPhones, iPads, and most recent OLED laptops.