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Tidy Tiānlán

#51bfd9
Notes

Tidy Tiānlán (#51BFD9) is a true cyan with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (191°, 64%, 58%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#51bfd9
RGB
rgb(81, 191, 217)
HSL
hsl(191, 64%, 58%)
HWB
hwb(191 32% 15%)
OKLCH
oklch(75.1% 0.106 216.0)
HSV
hsv(191, 63%, 85%)
LAB
lab(72.24% -23.53 -22.35)
LCH
lch(72.24% 32.45 223.53)
CMYK
cmyk(63%, 12%, 0%, 15%)

Etymology

Tidy
adjective

Old English tidig, timely — drifted in modern English to mean neat, orderly. Used as a color modifier for hues that read as composed and unfussy. Tidy beige, tidy gray: moderate saturation combined with optical neatness. Sits at the crisp-bucket alongside plain and modest.

Tiānlán
noun

Chinese for sky-blue — combining tiān (sky) and lán (blue). Used for the pale blue of clear-sky painting in Chinese landscape tradition and the tiānlán-cí (sky-blue glaze) of Song-dynasty porcelain. The color refers to a Song tiānlán glaze: a soft, slightly cool pale blue with the high gloss of fired ceramic glaze.

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

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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.

#51bfd9
Original
#adb9da
Protanopia
#99abd9
Deuteranopia
#00c9c7
Tritanopia
#a9a9a9
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).
Failon White
2.14:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
9.80:1

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