APCA is the new contrast method for WCAG 3, it is part of the SAPC perceptual contrast appearance model. At the SAPC dev site, there are some additional tools, click on "research mode" under the font display.
The difference between the WCAG 2 contrast and the new paradigm of APCA, is that SAPC/APCA are based on perception, whereas the old method is not. APCA also considers font weight and size, among other many things, making it far more accurate.
The research mode tools include a simplified version of the middle contrast experiments, and a constant contrast mode, where you can examine contrast over a range (the slider moves both the text and BG colors at the same time, maintaining constant contrast).
Comments
APCA is the new contrast method for WCAG 3, it is part of the SAPC perceptual contrast appearance model. At the SAPC dev site, there are some additional tools, click on "research mode" under the font display.
The difference between the WCAG 2 contrast and the new paradigm of APCA, is that SAPC/APCA are based on perception, whereas the old method is not. APCA also considers font weight and size, among other many things, making it far more accurate.
The research mode tools include a simplified version of the middle contrast experiments, and a constant contrast mode, where you can examine contrast over a range (the slider moves both the text and BG colors at the same time, maintaining constant contrast).