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Stormy Tonbo

#003a94
Notes

Stormy Tonbo (#003A94) is a deep 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 (216°, 100%, 29%) places it in the highly saturated band at a dark 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
#003a94
RGB
rgb(0, 58, 148)
HSL
hsl(216, 100%, 29%)
HWB
hwb(216 0% 42%)
OKLCH
oklch(38.0% 0.158 260.3)
HSV
hsv(216, 100%, 58%)
LAB
lab(27.19% 21.95 -53.68)
LCH
lch(27.19% 58.00 292.24)
CMYK
cmyk(100%, 61%, 0%, 42%)

Etymology

Stormy
adjective

Old English storm, storm — adjectival suffix -y. As a color modifier, stormy implies a deep-and-turbulent-and-cool-shifted quality, the dark cool-gray of Force-9-gale atmospheric-turbulence sky. Sits at the deep-and-turbulent end of the grid, parallel to thunderous and tempestuous in atmospheric register.

Tonbo
noun

The Japanese word for dragonfly — and tonbo-iro, the iridescent blue-green of dragonfly wing membranes. Tonbo is also a samurai-era heraldic motif representing victory (katsumushi, victory-insect). The color refers to a male blue-tail dragonfly's abdomen at rest: a saturated, slightly cool iridescent deep blue with the satin finish of structurally colored insect cuticle.

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.

#003a94
Original
#004797
Protanopia
#003a92
Deuteranopia
#005161
Tritanopia
#343434
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
10.33:1
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
2.03:1

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