Plumb Woad
Plumb Woad (#55AFBC) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (188°, 43%, 54%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Latin plumbum, lead — referring to the lead-weighted plumb-line of pre-modern carpentry. As a color modifier, plumb implies a clear-and-vertical-true quality where the hue carries the visual register of gravity-aligned-and-perfectly-vertical surface. Sits at the crisp-and-balanced end of the grid, parallel to level and squared in usage.
Isatis tinctoria, the European blue-dye plant whose leaves yield indigo-equivalent indigotin. Used by Pictish warriors as body paint and the dominant pre-industrial European blue dye until East Indian indigo displaced it in the seventeenth century. The color refers to a freshly woad-dyed wool: 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.