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Mourning Castor Cobalt

#034084
Notes

Mourning Castor Cobalt (#034084) 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 (212°, 96%, 26%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#034084
RGB
rgb(3, 64, 132)
HSL
hsl(212, 96%, 26%)
HWB
hwb(212 1% 48%)
OKLCH
oklch(38.0% 0.128 256.2)
P3
color(display-p3 0.0989 0.2468 0.4998)
HSV
hsv(212, 98%, 52%)
LAB
lab(27.71% 11.05 -42.94)
LCH
lch(27.71% 44.34 284.42)
CMYK
cmyk(98%, 52%, 0%, 48%)

Etymology

Mourning
adjective

Old English murnan, to grieve — present-participle of mourn, sharing root with Old Norse morna. As a color modifier, mourning implies the deep-and-funereal-and-formal-and-Victorian-mourning-period black-textile quality, the dark cool-formality of widow's-weeds-and-funeral-procession. Sits at the deep-and-funereal end of the grid, parallel to funereal and sepulchral.

Castor
modifier

Greek Κάστωρ, Gemini-twin-and-horseman. As a color modifier, castor implies a Gemini-twin-and-mortal-brother quality, the visual register of Gemini-Castor-and-Pollux-twin hand-Gemini-twin-and-mortal-brother Gemini-Castor-and-Pollux-twin-and-Argonaut castor-and-Gemini-twin-and-mortal-brother surfaces under Gemini-Castor-and-Pollux-twin-and-Argonaut spring-Gemini-and-Bortle-1-sky stellar-twin-light. Sits at the modifier-and-cosmic end of the grid, parallel to pollux and spica in usage.

Cobalt
noun

Element Co, atomic number 27 — German Kobold, goblin, named by miners who found the metal interfered with smelting silver ore. Cobalt blue is the cobalt-aluminate pigment introduced by Louis Jacques Thénard in 1802: a saturated, slightly green-shifted deep blue with the matte finish of mineral pigment in oil. Cooler than ultramarine, warmer than prussian, with the painter's weight of a pigment used by Renoir, Van Gogh, and Cézanne.

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.

#034084
Original
#144786
Protanopia
#003c83
Deuteranopia
#00515b
Tritanopia
#383838
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
10.14:1
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
2.07:1

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
##034084
Display P3
Display P3
color(display-p3 0.0989 0.2468 0.4998)
P3 has subtle headroomOKLCH chroma 0.128

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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