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Plumbed Aizome

#1c3680
Notes

Plumbed Aizome (#1C3680) 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 (224°, 64%, 31%) 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
#1c3680
RGB
rgb(28, 54, 128)
HSL
hsl(224, 64%, 31%)
HWB
hwb(224 11% 50%)
OKLCH
oklch(36.1% 0.129 265.6)
P3
color(display-p3 0.1338 0.2092 0.4839)
HSV
hsv(224, 78%, 50%)
LAB
lab(25.09% 18.54 -44.67)
LCH
lch(25.09% 48.37 292.54)
CMYK
cmyk(78%, 58%, 0%, 50%)

Etymology

Plumbed
adjective

Latin plumbum, lead — past-participle of plumb (to measure depth with a lead-weighted line). As a color modifier, plumbed implies a deep-and-cool quality measured-to-its-fullest-depth, the dark cool-gray of lead-and-pewter metallic surfaces. Sits at the deep-and-cool end of the grid, parallel to fathomless with metallic register.

Aizome
noun

The Japanese traditional indigo-dyeing technique — aizome — using Persicaria tinctoria (Japanese indigo) and natural fermentation in clay vats. The dyer is called aishi (indigo master), trained over decades. The color refers to a freshly aizome-dyed cotton: a saturated, slightly cool deep blue with the matte finish of multi-bath natural-indigo dye.

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.

#1c3680
Original
#004083
Protanopia
#00377f
Deuteranopia
#004855
Tritanopia
#363636
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
11.12:1
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
1.89:1

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
##1C3680
Display P3
Display P3
color(display-p3 0.1338 0.2092 0.4839)
P3 has subtle headroomOKLCH chroma 0.129

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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