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Firm Cornwall

#378f10
Notes

Firm Cornwall (#378F10) is a deep green 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 (102°, 80%, 31%) 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 violet. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#378f10
RGB
rgb(55, 143, 16)
HSL
hsl(102, 80%, 31%)
HWB
hwb(102 6% 44%)
OKLCH
oklch(57.4% 0.174 138.9)
P3
color(display-p3 0.3137 0.5534 0.1728)
HSV
hsv(102, 89%, 56%)
LAB
lab(52.39% -47.55 52.33)
LCH
lch(52.39% 70.71 132.26)
CMYK
cmyk(62%, 0%, 89%, 44%)

Etymology

Firm
adjective

Latin firmus, strong / stable — sharing root with English farm (originally a fixed-yearly-rental). As a color modifier, firm implies a saturated-and-resolute quality where the hue holds its visual position without wavering. Sits at the bold-and-firm end of the grid, parallel to steadfast and unwavering in usage.

Cornwall
noun

The southwestern English county — and the rolling green hills of Cornish moors and the Cornish Heritage Coast hedgerows. Cornwall color refers to a Cornish hillside in late spring: a saturated, slightly cool deep yellow-green with the matte finish of grazed pasture grass. Drier than verdant.

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.

#378f10
Original
#938100
Protanopia
#897a22
Deuteranopia
#2d8a79
Tritanopia
#737373
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).
AA Largeon White
4.12:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
5.10:1

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
##378F10
Display P3
Display P3
color(display-p3 0.3137 0.5534 0.1728)
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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