APCA/SAPC - the new way to calculate contrast.

WCAG 3 is now moving to a new algorithm for measuring contrast, called APCA (Advanced Perceptual Contrast Algorithm).

It's much more truthful in its results than the previous method used by WCAG 2.

The old contrast ratios (7:1 for example) are replaced with a contrast level that goes from 0 -> ~107.

The guidelines recommend:

Read more: ACPA repo & Dan Hollicks tweet

contrast val comment