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Inviting Stream

#51a6d5
Notes

Inviting Stream (#51A6D5) is a true azure 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 (201°, 61%, 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#51a6d5
RGB
rgb(81, 166, 213)
HSL
hsl(201, 61%, 58%)
HWB
hwb(201 32% 16%)
OKLCH
oklch(69.2% 0.107 235.5)
P3
color(display-p3 0.4036 0.6433 0.8180)
HSV
hsv(201, 62%, 84%)
LAB
lab(64.82% -11.63 -31.55)
LCH
lch(64.82% 33.63 249.77)
CMYK
cmyk(62%, 22%, 0%, 16%)

Etymology

Inviting
adjective

Latin invītāre, to invite — present-participle of invite. As a color modifier, inviting implies a clear-and-cordial-and-encouraging quality where the hue carries the visual register of warm-inviting-and-encouraging entrance-foyer color tone. Sits at the crisp-and-cheerful end of the grid, parallel to welcoming and hospitable in usage.

Stream
noun

A narrow flowing body of fresh water — smaller than a river, larger than a creek. The color refers to a clear stream over a gravel bed in temperate woodland: a soft, slightly green-shifted blue with the optical clarity of unsilted water. Cooler than aqua, lighter than tide, with the hydrological weight of a word that appears across nearly every English landscape vocabulary.

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.

#51a6d5
Original
#90a5d7
Protanopia
#7d97d4
Deuteranopia
#00b2b6
Tritanopia
#979797
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
2.70:1
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
7.77:1

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
##51A6D5
Display P3
Display P3
color(display-p3 0.4036 0.6433 0.8180)
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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