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Stamped Celtic Turquoise

#40bbc8
Notes

Stamped Celtic Turquoise (#40BBC8) 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 (186°, 55%, 52%) 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
#40bbc8
RGB
rgb(64, 187, 200)
HSL
hsl(186, 55%, 52%)
HWB
hwb(186 25% 22%)
OKLCH
oklch(73.0% 0.107 205.2)
P3
color(display-p3 0.3964 0.7235 0.7753)
HSV
hsv(186, 68%, 78%)
LAB
lab(70.03% -29.25 -16.46)
LCH
lch(70.03% 33.56 209.37)
CMYK
cmyk(68%, 7%, 0%, 22%)

Etymology

Stamped
adjective

Old English stempan, to stamp — past-participle of stamp. As a color modifier, stamped implies a clear-and-impressed-and-repeating quality, the crisp color of William-Morris-and-Liberty-of-London block-printed-textile carefully-impressed pattern. Sits at the crisp-and-printed end of the grid, parallel to printed and engraved in usage.

Celtic
modifier

Latin Celticus, of-the-Celts. As a color modifier, celtic implies a knotwork-and-La-Tène quality, the visual register of Irish-and-Welsh-and-Scottish Celtic-knotwork hand-carved bronze-and-stone metalwork-and-illuminated-manuscript surfaces under Celtic-Irish-Welsh-Scottish illuminated-manuscript-tradition light. Sits at the modifier-and-cultural end of the grid, parallel to norse and welsh in usage.

Turquoise
noun

The hydrated copper-aluminum phosphate mined in Persia and the American Southwest for thousands of years — the firuze of Iran, the chalchihuitl of Mesoamerica, the heart of Pueblo and Navajo silverwork. The color refers to a fine Sleeping Beauty turquoise from Arizona: a saturated, slightly green-shifted blue with the slight matrix of host-rock veining. Brighter than persian, lighter than cerulean.

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.

#40bbc8
Original
#acb4c9
Protanopia
#98a5c8
Deuteranopia
#00c3bf
Tritanopia
#a2a2a2
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
2.29:1
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
9.16:1

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
##40BBC8
Display P3
Display P3
color(display-p3 0.3964 0.7235 0.7753)
P3 has subtle headroomOKLCH chroma 0.107

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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