Spartan Idanthrene
Spartan Idanthrene (#5663F2) is a true blue with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (235°, 86%, 64%) 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 yellow. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Greek Spartiátēs, of Sparta — adjectival suffix referring to the Lacedaemonian warrior city. As a color modifier, spartan implies a saturated-and-disciplined-and-formal quality, the deep-rich color of Spartan-hoplite military-class crimson-and-bronze armor-and-cloak. Sits at the bold-and-formal end of the grid, parallel to austere and stern in tone.
The trade name for vat blue synthetic dyes — particularly Idanthrene Blue RS (BASF, 1901), a polycyclic aromatic dye that displaced indigo for many industrial textile applications. The color refers to Idanthrene-dyed industrial cotton: a saturated, slightly cool deep blue with the matte finish of synthetic-pigment-and-cotton.
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.