On the left, the existing WCAG 2.x 1.4.3
On the right, the challenger, WCAG 3's APCA
IN THIS TEST: Body text, headlines, and non-text (buttons). Which do you find more readable?
(Note: on the left is WCAG 2 at AA or better, but it fails APCA)
Some questions asked recently: How about CVD (color impaired)? How about about 3 way color? 3 way usually involved a button, text on the button, and body text on the page. 1.4.3 tried to fit a center grey (nope!) APCA is perceptually accurate, allowing full body text contrast..+
-...while still allowing intermediate contrasts for larger shapes like buttons with spatial frequency based contrast easing, giving designers more and truer flexibility AND vastly improving readability.
As for CVD? Look at the above example after processing in the CVD sim:
Revised font lookup tables.
NEW: when used as body text, table cells outlined in yellow should have Lc 15 added to the listed contrast figure (see the +15). Fonts outlined in blue/teal (ish) may use the value as listed, but may benefit from an additional Lc10 to Lc15. ++
--For developers, there are ready-to-go arrays of the look up tables, presorted by Lc value, and also with a table of pre-calculated interpolation values, and more.