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Firm Sapporo

#663fb3
Notes

Firm Sapporo (#663FB3) is a true indigo 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 (260°, 48%, 47%) 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 lime. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#663fb3
RGB
rgb(102, 63, 179)
HSL
hsl(260, 48%, 47%)
HWB
hwb(260 25% 30%)
OKLCH
oklch(47.7% 0.175 294.3)
HSV
hsv(260, 65%, 70%)
LAB
lab(37.18% 43.32 -55.83)
LCH
lch(37.18% 70.66 307.81)
CMYK
cmyk(43%, 65%, 0%, 30%)

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.

Sapporo
noun

Capital of Japan's Hokkaido island — a city famous for its annual February Yuki Matsuri (Snow Festival) with deep-twilight blue lighting on illuminated snow sculptures along the Ōdōri Park boulevard. Sapporo color refers to a Yuki Matsuri night-sky over an illuminated snow sculpture: a saturated, slightly cool deep blue-violet with the optical complexity of artificial illumination on snow-reflected sky.

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.

#663fb3
Original
#0059b7
Protanopia
#0056b1
Deuteranopia
#515a73
Tritanopia
#505050
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
7.17:1
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
2.93:1

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