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Heroic Tonbo

#3b7fd3
Notes

Heroic Tonbo (#3B7FD3) is a true azure with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (213°, 63%, 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
#3b7fd3
RGB
rgb(59, 127, 211)
HSL
hsl(213, 63%, 53%)
HWB
hwb(213 23% 17%)
OKLCH
oklch(59.4% 0.146 255.2)
HSV
hsv(213, 72%, 83%)
LAB
lab(52.74% 6.68 -49.47)
LCH
lch(52.74% 49.92 277.69)
CMYK
cmyk(72%, 40%, 0%, 17%)

Etymology

Heroic
adjective

Latin hēroicus, of a hero — derived from Greek hērōs. As a color modifier, heroic implies a saturated-and-monumental-and-victorious quality, the deep-rich color of Wagner-and-Sibelius late-Romantic-era musical-and-painterly heroic-mode. Sits at the bold-and-celebratory end of the grid, parallel to triumphant and valiant.

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

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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.

#3b7fd3
Original
#5886d6
Protanopia
#3f77d1
Deuteranopia
#00939f
Tritanopia
#777777
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
4.07:1
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
5.16:1

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