Contrast Matrices & APCA

Layer 06 // Accessibility

The standard WCAG 2.1 contrast ratio mathematical formula is notoriously flawed, especially for dark mode interfaces. It treats light and dark text symmetrically, which contradicts human perception.

The Advanced Perceptual Contrast Algorithm (APCA) for WCAG 3.0 uses a model closer to human vision, resulting in Lightness Contrast (Lc) values.

APCA Contrast Tool