Color blind simulator
Run your palette through the four major color-vision deficiencies. Pairs that collapse get flagged — the URL is the palette.
| Pair | Normal ΔE | Worst case |
|---|---|---|
Authoritative Aegean ↔ Sylvan Slate #3B82F6 · #6B7280 | ΔE 58.9 | AchromatΔE 3.6 |
Fire Red ↔ Sylvan Slate #EF4444 · #6B7280 | ΔE 80.3 | AchromatΔE 4.0 |
Fire Red ↔ Authoritative Aegean #EF4444 · #3B82F6 | ΔE 113.8 | AchromatΔE 7.6 |
Beaming Mauritius ↔ Strobing Amber #22C55E · #EAB308 | ΔE 79.0 | AchromatΔE 8.6 |
Beaming Mauritius ↔ Authoritative Aegean #22C55E · #3B82F6 | ΔE 132.1 | AchromatΔE 12.4 |
Fire Red ↔ Beaming Mauritius #EF4444 · #22C55E | ΔE 127.3 | DeutanΔE 12.8 |
Five views, one palette
Roughly one in twelve men and one in two hundred women see color differently than the trichromatic baseline most palettes are designed against. The simulation is computed with the Machado–Oliveira–Fernandes (2009) physiological model — the same matrices used by Adobe and the W3C accessibility samples. The output is a fair approximation of perceived hue for full dichromats; lived experience varies by the depth of each individual's deficiency.
Distinct pairs that quietly collapse
The flagged pairs were comfortably distinct under normal vision but drop below the perceptual-distance floor under at least one CVD mode. That's the meaningful failure: two roles in your UI that trichromats can tell apart, but a deutan or protan viewer cannot. The fix is rarely a different hue — it's adding a non-color signal (icon, label, position) so the meaning carries when hue is missing.
Every palette has its own page
A vision URL looks like /vision/ef4444-22c55e-3b82f6. Two to twelve hexes, hyphenated — same shape as a palette URL. Bookmark a problematic pairing, or drop the link in a ticket so a designer sees the same five rows you saw.