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Tough Plumbago

#1b6cbc
Notes

Tough Plumbago (#1B6CBC) is a true azure with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (210°, 75%, 42%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#1b6cbc
RGB
rgb(27, 108, 188)
HSL
hsl(210, 75%, 42%)
HWB
hwb(210 11% 26%)
OKLCH
oklch(52.8% 0.146 252.7)
HSV
hsv(210, 86%, 74%)
LAB
lab(45.06% 6.32 -48.60)
LCH
lch(45.06% 49.01 277.41)
CMYK
cmyk(86%, 43%, 0%, 26%)

Etymology

Tough
adjective

Old English tōh, firm / tenacious — sharing root with German zäh. As a color modifier, tough implies a saturated-and-resilient quality where the hue resists fading-and-modulation through its strong pigmentation. Sits at the bold-and-resilient end of the grid, parallel to rugged and hardy in usage.

Plumbago
noun

Plumbago auriculata, the South African shrub whose pale-blue five-petaled flowers cluster on stems through summer. The Latin name traces to plumbum, lead, for the plant's purported ability to cure lead-related skin afflictions. The color refers to a fresh plumbago bloom: a soft, slightly violet-shifted very pale blue with the matte finish of a five-petaled flower. Lighter than larkspur, cooler than periwinkle.

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

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Harmonies

Accessibility

Color-vision simulation

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.

#1b6cbc
Original
#4372bf
Protanopia
#2564ba
Deuteranopia
#007f8b
Tritanopia
#616161
Achromatopsia
WCAG contrast

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.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon White
5.36:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon Black
3.92:1

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