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Trustworthy Cyan

#40d5f5
Notes

Trustworthy Cyan (#40D5F5) is a true cyan with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (191°, 90%, 61%) places it in the highly saturated band at a mid lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. 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
#40d5f5
RGB
rgb(64, 213, 245)
HSL
hsl(191, 90%, 61%)
HWB
hwb(191 25% 4%)
OKLCH
oklch(80.9% 0.128 215.7)
HSV
hsv(191, 74%, 96%)
LAB
lab(79.19% -28.33 -26.85)
LCH
lch(79.19% 39.03 223.47)
CMYK
cmyk(74%, 13%, 0%, 4%)

Etymology

Trustworthy
adjective

Old English trēow, trust — adjectival suffix -worthy. As a color modifier, trustworthy implies a clear-and-reliable-and-honest quality where the hue carries the visual register of confidence-deserving-and-faithful-performance design-element. Sits at the crisp-and-honest end of the grid, parallel to reliable and dependable in usage.

Cyan
noun

From the Greek kyanos, deep blue, originally referring to the lapis-derived blue of antiquity. In modern usage, cyan is one of the four printing primaries (with magenta, yellow, and black) and an additive primary on screens. The color refers to a pure CMYK cyan tile: a saturated, clean blue-green with the optical brightness of an additive-color primary. Cooler than turquoise, lighter than cerulean, with the technical specificity of a color defined by a printing-press standard.

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.

#40d5f5
Original
#bfcef7
Protanopia
#a6bcf5
Deuteranopia
#00e1df
Tritanopia
#b8b8b8
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
1.74:1
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
12.05:1

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