Sure Copper
Sure Copper (#B5651E) is a true orange with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (28°, 72%, 41%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary azure. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old French seur, certain — used as a color modifier since the medieval period for hues that read as confident and stable. Sure red, sure blue: moderate saturation combined with optical commitment. Sits at the crisp-bucket center alongside steady and true.
Element Cu, atomic number 29 — one of the first metals worked by humans, smelted in Anatolia and the Levant by the fourth millennium BCE. The color refers to freshly polished copper before oxidation: a warm, slightly red metallic orange with the satin finish of a coin or a kettle. Left in air, it dulls to brown; left in salt air, it greens to verdigris. The starting color of every copper roof.
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.