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Smooth Cowslip

#637833
Notes

Smooth Cowslip (#637833) is a deep lime with an earthy character. It leans grounded and natural, the kind of color that plays well with wood, clay, linen, and warm neutrals. Its HSL profile (78°, 40%, 34%) 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 indigo. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#637833
RGB
rgb(99, 120, 51)
HSL
hsl(78, 40%, 34%)
HWB
hwb(78 20% 53%)
OKLCH
oklch(54.0% 0.098 123.8)
HSV
hsv(78, 57%, 47%)
LAB
lab(47.40% -19.27 34.81)
LCH
lch(47.40% 39.79 118.96)
CMYK
cmyk(18%, 0%, 58%, 53%)

Etymology

Smooth
adjective

Old English smōþ, level, polished — used as a color modifier since the seventeenth century for hues that read as continuous without texture or break. Smooth tan, smooth gray: moderate saturation combined with optical evenness. Sits in the crisp-bucket alongside even.

Cowslip
noun

Primula veris, the European meadow primrose whose yellow flower clusters appear in late spring. The name traces to Old English cū-slyppe, cow-slop (i.e., cow dung — for where it grew). The color refers to fresh cowslip in May meadow: a soft, slightly red-shifted pale yellow with the matte finish of small five-petaled flowers in tight clusters.

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.

#637833
Original
#7e712c
Protanopia
#7c7037
Deuteranopia
#677369
Tritanopia
#6f6f6f
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).
AAon White
4.92:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon Black
4.26:1

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