Function Signature

js

deltaE76(hexA: string, hexB: string): number

Parameters

hexA (string): First HEX color string.
hexB (string): Second HEX color string.

Return Value

Returns a number representing the perceptual distance (ΔE) between the two colors. Smaller values mean the colors are closer perceptually.

js

deltaE76("#ff6600", "#ff6600");
// 0 (identical colors)

deltaE76("#ff6600", "#ff6622");
// ~2.5 (barely noticeable)

deltaE76("#ff6600", "#00aaff");
// ~60 (very different)

Examples

js

// Compare similar oranges
console.log(deltaE76("#ff6600", "#ff6633"));
// ~3 (noticeable but small difference)

// Compare orange and blue
console.log(deltaE76("#ff6600", "#0000ff"));
// ~70 (drastic difference)

Implementation Details

Converts each HEX color to RGB using hexToRgb.
Transforms RGB to Lab with rgbToLab.
Computes ΔE as the Euclidean distance between the Lab coordinates:
ΔE = sqrt((ΔL)^2 + (Δa)^2 + (Δb)^2).
This is the simplest form of color difference (CIE76).

Usage Notes

ΔE < 1: Difference is imperceptible to the human eye.
ΔE < 2: Only perceptible under close observation.
ΔE ~ 2–10: Perceptible at a glance.
ΔE > 10: Colors are clearly different.
ΔE > 50: Colors appear opposite or unrelated.