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Reinforced Rhine

#138ffd
Notes

Reinforced Rhine (#138FFD) is a true azure 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 (208°, 98%, 53%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#138ffd
RGB
rgb(19, 143, 253)
HSL
hsl(208, 98%, 53%)
HWB
hwb(208 7% 1%)
OKLCH
oklch(64.7% 0.190 252.5)
HSV
hsv(208, 92%, 99%)
LAB
lab(58.86% 9.30 -63.14)
LCH
lch(58.86% 63.82 278.38)
CMYK
cmyk(92%, 43%, 0%, 1%)

Etymology

Reinforced
adjective

Latin re- plus inforce — past-participle of reinforce. As a color modifier, reinforced implies a saturated-and-doubled-up-and-strengthened quality where the hue carries layered pigmentation for maximum visual presence. Sits at the bold-and-fortified end of the grid, parallel to fortified and buttressed.

Rhine
noun

The Rhine River — Europe's third-longest, flowing from the Swiss Alps to the Dutch North Sea. Rhine color refers to mid-depth Rhine River water at Lorelei on the Mittelrhein: a saturated, slightly cool deep blue with the optical depth of Alpine-glacier-fed European river water.

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.

#138ffd
Original
#5498ff
Protanopia
#2185fb
Deuteranopia
#00aaba
Tritanopia
#7d7d7d
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).
AA Largeon White
3.29:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
6.38:1

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