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Practical Apse Kingfisher

#40abbf
Notes

Practical Apse Kingfisher (#40ABBF) is a true cyan 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 (189°, 50%, 50%) 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
#40abbf
RGB
rgb(64, 171, 191)
HSL
hsl(189, 50%, 50%)
HWB
hwb(189 25% 25%)
OKLCH
oklch(68.8% 0.100 212.3)
P3
color(display-p3 0.3726 0.6617 0.7385)
HSV
hsv(189, 66%, 75%)
LAB
lab(64.94% -23.99 -19.21)
LCH
lch(64.94% 30.73 218.68)
CMYK
cmyk(66%, 10%, 0%, 25%)

Etymology

Practical
adjective

Greek praktikós, practical — adjectival suffix -al. As a color modifier, practical implies a clear-and-purpose-fit-and-everyday quality where the hue carries the visual register of Shaker-and-Quaker utilitarian-and-functional everyday-life craft. Sits at the crisp-and-functional end of the grid, parallel to functional and workmanlike in usage.

Apse
modifier

Latin absis, vault / arch-recess. As a color modifier, apse implies a semicircular-vaulted-altar-end quality, the visual register of Romanesque-and-Byzantine-cathedral hand-laid mosaic-and-fresco-decorated semicircular altar-end vaulted-apse architectural surfaces under candle-and-incense apse light. Sits at the modifier-and-architecture end of the grid, parallel to nave and aisle in usage.

Kingfisher
noun

The family Alcedinidae — particularly Alcedo atthis, the European common kingfisher whose iridescent turquoise-blue plumage gives the color its name. The color refers to a male European kingfisher's wing: a saturated, slightly cool deep blue-green with the iridescent satin finish of structurally colored feathers.

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.

#40abbf
Original
#9ba5c0
Protanopia
#8998bf
Deuteranopia
#00b3b1
Tritanopia
#969696
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
2.69:1
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
7.80:1

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
##40ABBF
Display P3
Display P3
color(display-p3 0.3726 0.6617 0.7385)
P3 has subtle headroomOKLCH chroma 0.100

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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