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:
- 15 - Minimum for non-text elements
- 30 - Absolute min for any text
- 45 - Min for large text (the old 3:1)
- 60 - Min for body text (the old 4.5:1)
- 75 - Stort vitt korsmärke Preferred level for body text
Read more: ACPA repo & Dan Hollicks tweet