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Calm Umbra

#180310
Notes

Calm Umbra (#180310) is a deep magenta 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 (323°, 78%, 5%) 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 green. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#180310
RGB
rgb(24, 3, 16)
HSL
hsl(323, 78%, 5%)
HWB
hwb(323 1% 91%)
OKLCH
oklch(15.0% 0.048 343.9)
P3
color(display-p3 0.0837 0.0153 0.0604)
HSV
hsv(323, 88%, 9%)
LAB
lab(2.68% 9.04 -2.83)
LCH
lch(2.68% 9.47 342.63)
CMYK
cmyk(0%, 88%, 33%, 91%)

Etymology

Calm
adjective

Latin calma, heat of the day — paradoxically drifted in Italian to mean stillness. Used as a color modifier since the seventeenth century for hues that read as untroubled. Calm blue, calm gray: moderate saturation combined with optical quiet. Sits at the crisp-bucket near quiet and steady.

Umbra
noun

Latin umbra, shadow — adopted into astronomy as the technical term for the deep-shadow inner cone of an eclipse shadow, where the occulting body completely blocks the light source. Umbra color refers to a total solar eclipse ground-level observer's path of totality darkness: a saturated, slightly cool deep black with the optical complexity of total-solar-eclipse atmospheric scattering against a shadow-cone-occluded sun-disk.

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.

#180310
Original
#040710
Protanopia
#0a0b0f
Deuteranopia
#1a0307
Tritanopia
#080808
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
19.82:1
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
1.06:1

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
##180310
Display P3
Display P3
color(display-p3 0.0837 0.0153 0.0604)
Inside sRGBOKLCH chroma 0.048

This color sits well within the sRGB cube. P3 and sRGB share the gray axis and most desaturated tones, so a P3 display renders this identically to an sRGB display.

Related Colors

Canvas