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Steadfast Plumbago

#155cab
Notes

Steadfast Plumbago (#155CAB) 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 (212°, 78%, 38%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#155cab
RGB
rgb(21, 92, 171)
HSL
hsl(212, 78%, 38%)
HWB
hwb(212 8% 33%)
OKLCH
oklch(47.8% 0.143 255.0)
HSV
hsv(212, 88%, 67%)
LAB
lab(39.16% 9.43 -48.12)
LCH
lch(39.16% 49.04 281.08)
CMYK
cmyk(88%, 46%, 0%, 33%)

Etymology

Steadfast
adjective

Old English stede-fæst, fixed in place — sharing root with German stetig. As a color modifier, steadfast implies a saturated-and-unwavering quality where the hue maintains its visual character without modulation. Sits at the bold-and-firm end of the grid, parallel to unwavering and firm 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

Click any swatch to explore

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.

#155cab
Original
#3163ae
Protanopia
#0756a9
Deuteranopia
#006f7b
Tritanopia
#535353
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
6.66:1
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
3.15:1

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