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Stained Observatory

#183aa3
Notes

Stained Observatory (#183AA3) is a true blue 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 (225°, 74%, 37%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#183aa3
RGB
rgb(24, 58, 163)
HSL
hsl(225, 74%, 37%)
HWB
hwb(225 9% 36%)
OKLCH
oklch(40.0% 0.174 265.1)
P3
color(display-p3 0.1285 0.2244 0.6153)
HSV
hsv(225, 85%, 64%)
LAB
lab(29.07% 29.33 -59.73)
LCH
lch(29.07% 66.54 296.15)
CMYK
cmyk(85%, 64%, 0%, 36%)

Etymology

Stained
adjective

Old French desteindre, to discolor — past-participle of stain. As a color modifier, stained implies a deep-pigment-and-permanent quality where the hue has bonded with the substrate fiber. Sits at the deep-and-pigmented end of the grid, parallel to dyed and suffused in usage.

Observatory
noun

An astronomical research facility — particularly the deep-blue interior paint of optical observatories like Mount Wilson, Palomar, and Mauna Kea. The deep blue minimizes stray-light reflection inside the dome. The color refers to the painted interior of a research-grade optical observatory: a saturated, slightly cool very deep blue with the matte finish of low-reflectance enamel.

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.

#183aa3
Original
#004ba6
Protanopia
#003ea1
Deuteranopia
#005669
Tritanopia
#3a3a3a
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
9.66:1
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
2.17:1

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
##183AA3
Display P3
Display P3
color(display-p3 0.1285 0.2244 0.6153)
P3 has subtle headroomOKLCH chroma 0.174

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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