• Success Criterion 1.4.3
  • Conformance level AA

Semi-Transparent Text That Fails the Contrast Minimum

1.4.3 — Contrast (Minimum)

Scenario

Setting

A car-rental site's checkout flow

What’s wrong

Semi-transparent text/backgrounds (opacity/alpha) computing below threshold.

Example

A tester reviewing a car-rental site's checkout flow finds this: semi-transparent text/backgrounds (opacity/alpha) computing below threshold.

Why it matters

Low-vision and older readers, plus anyone viewing a dim or sunlit screen. On a car-rental site's checkout flow, that means they miss information conveyed only by color.

How to test

Measure text with any opacity/alpha transparency against what's actually behind it (not the nominal color): compute the effective blended contrast.

How to fix

The text must meet at least 4.5:1 contrast (3:1 for large text) against its actual background in every state (default, hover, focus, selected).

Outcome

With the fix in place on a car-rental site's checkout flow, they tell the information apart without relying on color.

Who is affected

Low-vision and older readers, plus anyone viewing a dim or sunlit screen.

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