colors
Back to gallery

Firm Plumbago

#337ad9
Notes

Firm Plumbago (#337AD9) 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 (214°, 69%, 53%) 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
#337ad9
RGB
rgb(51, 122, 217)
HSL
hsl(214, 69%, 53%)
HWB
hwb(214 20% 15%)
OKLCH
oklch(58.4% 0.162 256.9)
P3
color(display-p3 0.2757 0.4723 0.8246)
HSV
hsv(214, 76%, 85%)
LAB
lab(51.42% 10.94 -54.99)
LCH
lch(51.42% 56.07 281.25)
CMYK
cmyk(76%, 44%, 0%, 15%)

Etymology

Firm
adjective

Latin firmus, strong / stable — sharing root with English farm (originally a fixed-yearly-rental). As a color modifier, firm implies a saturated-and-resolute quality where the hue holds its visual position without wavering. Sits at the bold-and-firm end of the grid, parallel to steadfast and unwavering 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.

#337ad9
Original
#4a83dd
Protanopia
#2874d7
Deuteranopia
#00909f
Tritanopia
#727272
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).
AA Largeon White
4.26:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
4.93:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##337AD9
Display P3
Display P3
color(display-p3 0.2757 0.4723 0.8246)
P3 has subtle headroomOKLCH chroma 0.162

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

Related Colors

Canvas