Tenacious Niloo
Tenacious Niloo (#1E4BA2) is a true 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 (220°, 69%, 38%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Latin tenāx, holding-fast — adjectival suffix -ous. As a color modifier, tenacious implies a saturated-and-clinging quality where the hue grips its substrate with stubborn pigmentation. Sits at the bold-and-resilient end of the grid, parallel to unyielding and adamant in usage.
The Persian word for indigo plant — borrowed from Sanskrit nīla (dark blue). Niloo names the plant Indigofera tinctoria in Persian and the saturated deep blue dye it produces. The color refers to a freshly niloo-dyed Persian carpet: a saturated, slightly cool deep blue with the matte finish of plant-and-mordant dye.
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.