Contrast-Weighted Visibility Score

The problem

It is difficult to accurately judge how much a piece of text or an object will stand out against a background just by looking at the colors.

What it does

It calculates a score by measuring the difference between two colors while accounting for how bright they actually appear to the human eye.

Why it matters

It provides a more accurate way to measure how much an element will pop against its background.

Validation

It was run inside an isolated container with no network access. This is the exact command and the real output it produced — captured process output, not written by a model.

$ python3 visibility_score.py
Contrast-Weighted Visibility Score: 21.0320

A screenshot of that run.

A clean run proves this does what is shown above, in a CPU-only sandbox. It is a small research demo — not a production tool, and nothing here was published anywhere.

The code

All of it — 42 lines, one file, standard library only.

# Contrast-Weighted Visibility Score Calculator
import math

def euclidean_distance(fg, bg):
    """
    Calculate Euclidean distance between two RGB colors
    """
    return math.sqrt(sum((a - b)**2 for a, b in zip(fg, bg)))

def luminance(rgb):
    """
    Calculate relative luminance (0-1) from RGB values (0-255)
    """
    r, g, b = [x / 255.0 for x in rgb]
    return 0.2126 * r + 0.7152 * g + 0.0722 * b

import sys

def contrast_ratio(fg, bg):
    """
    Calculate WCAG luminance contrast ratio
    """
    L_fg = luminance(fg)
    L_bg = luminance(bg)
    L1 = max(L_fg, L_bg)
    L2 = min(L_fg, L_bg)
    return (L1 + 0.05) / (L2 + 0.05)

def visibility_score(fg, bg):
    """
    Calculate contrast-weighted visibility score
    """
    distance = euclidean_distance(fg, bg)
    cr = contrast_ratio(fg, bg)
    return distance / cr

if __name__ == "__main__":
    # Example usage with white on black
    fg = (255, 255, 255)  # White
    bg = (0, 0, 0)        # Black
    score = visibility_score(fg, bg)
    print(f"Contrast-Weighted Visibility Score: {score:.4f}")