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Authoritative Sumi

#383fa8
Notes

Authoritative Sumi (#383FA8) is a true blue with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (236°, 50%, 44%) 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 yellow. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#383fa8
RGB
rgb(56, 63, 168)
HSL
hsl(236, 50%, 44%)
HWB
hwb(236 22% 34%)
OKLCH
oklch(42.9% 0.166 274.1)
HSV
hsv(236, 67%, 66%)
LAB
lab(32.31% 31.49 -57.38)
LCH
lch(32.31% 65.45 298.76)
CMYK
cmyk(67%, 63%, 0%, 34%)

Etymology

Authoritative
adjective

Latin auctōritāt-, authority — adjectival suffix -ive. As a color modifier, authoritative implies a saturated-and-formal-imperative quality where the hue carries decisional weight and institutional credibility. Sits at the bold-and-authoritative end of the grid, parallel to commanding and magisterial in usage.

Sumi
noun

Japanese ink stick, made from soot of pine resin or sesame oil mixed with animal-glue binder, used in sumi-e brush painting and shodō calligraphy. Although nominally black, undiluted sumi on rice paper carries a deep blue-violet undertone. Sumi color refers to a heavily-loaded sumi brushstroke: a saturated, slightly cool deep blue-violet with the matte finish of pine-soot ink on absorbent washi.

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.

#383fa8
Original
#0051ab
Protanopia
#0047a6
Deuteranopia
#00596d
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
8.59:1
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
2.44:1

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