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Sable Slate

#18388b
Notes

Sable Slate (#18388B) 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 (223°, 71%, 32%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. 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
#18388b
RGB
rgb(24, 56, 139)
HSL
hsl(223, 71%, 32%)
HWB
hwb(223 9% 45%)
OKLCH
oklch(37.3% 0.143 264.4)
P3
color(display-p3 0.1260 0.2167 0.5252)
HSV
hsv(223, 83%, 55%)
LAB
lab(26.41% 21.15 -49.39)
LCH
lch(26.41% 53.73 293.18)
CMYK
cmyk(83%, 60%, 0%, 45%)

Etymology

Sable
noun

Martes zibellina, the Eurasian sable — a small mustelid of Siberian taiga whose deep brown-black fur was the most prized mammalian pelt of the Russian and Chinese imperial courts. The color refers to a fresh sable pelt: a deep, slightly warm near-black with the satin finish of densely packed guard hairs. Warmer than ink, glossier than coal, with the courtly weight of a fur reserved for tsars and emperors.

Slate
noun

A fine-grained metamorphic rock formed from compressed shale — fissile, durable, and the standard roofing material for Welsh and Vermont houses since the nineteenth century. The color refers to a freshly split piece of Welsh slate: a soft, slightly muted gray-blue with the matte finish of a layered mineral cleavage. Cooler than steel, lighter than navy, with the architectural weight of a roof material that lasts a hundred years.

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.

#18388b
Original
#00448e
Protanopia
#003989
Deuteranopia
#004d5c
Tritanopia
#373737
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
10.62:1
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
1.98:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##18388B
Display P3
Display P3
color(display-p3 0.1260 0.2167 0.5252)
P3 has subtle headroomOKLCH chroma 0.143

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

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