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Unwavering Tsuyukusa

#1548b5
Notes

Unwavering Tsuyukusa (#1548B5) 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 (221°, 79%, 40%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#1548b5
RGB
rgb(21, 72, 181)
HSL
hsl(221, 79%, 40%)
HWB
hwb(221 8% 29%)
OKLCH
oklch(44.3% 0.181 262.6)
HSV
hsv(221, 88%, 71%)
LAB
lab(34.25% 26.80 -62.00)
LCH
lch(34.25% 67.55 293.38)
CMYK
cmyk(88%, 60%, 0%, 29%)

Etymology

Unwavering
adjective

Old English un- (negation) plus wafrian (to flicker). As a color modifier, unwavering implies a saturated-and-constant quality where the hue maintains its full strength without flicker or shift. Sits at the bold-and-firm end of the grid, parallel to steadfast and firm in usage.

Tsuyukusa
noun

Commelina communis, the Japanese dayflower — a wildflower whose deep blue flowers were used in the seventeenth century as a textile dye and aobana paper for yuzen dyeing patterns. Tsuyukusa-iro (露草色) refers to the saturated blue of fresh dayflower. The color refers to a fresh dayflower bloom: a saturated, slightly cool deep blue with the satin finish of three-petaled flower.

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.

#1548b5
Original
#0058b9
Protanopia
#004ab3
Deuteranopia
#006477
Tritanopia
#454545
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).
AAAon White
8.00:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
Failon Black
2.63:1

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