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Calm Castor Moss

#0d553e
Notes

Calm Castor Moss (#0D553E) is a deep teal 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 (161°, 73%, 19%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#0d553e
RGB
rgb(13, 85, 62)
HSL
hsl(161, 73%, 19%)
HWB
hwb(161 5% 67%)
OKLCH
oklch(40.1% 0.078 165.8)
P3
color(display-p3 0.1493 0.3282 0.2491)
HSV
hsv(161, 85%, 33%)
LAB
lab(31.65% -27.44 7.47)
LCH
lch(31.65% 28.44 164.77)
CMYK
cmyk(85%, 0%, 27%, 67%)

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.

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.

Moss
noun

Bryophyta — the nonvascular plants that colonized land 470 million years ago, before vascular plants and far before flowers. The color refers to a thick mat of Hypnum or sphagnum on a temperate forest floor: a soft, slightly yellow-shifted green with the velvet texture of millimeter-scale leaves. Dustier than fern, deeper than lichen, with the slow patience of a plant that lives by absorbing rain through its surface.

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.

#0d553e
Original
#534e3d
Protanopia
#4a4840
Deuteranopia
#00554f
Tritanopia
#444444
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
8.80:1
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
2.39:1

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
##0D553E
Display P3
Display P3
color(display-p3 0.1493 0.3282 0.2491)
Inside sRGBOKLCH chroma 0.078

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.

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