No it doesn't? The screenshot of the calculator in the blog post very clearly shows that white has a greater contrast according to APCA. (If the negative numbers are confusing, you can also put the colors into a BridgePCA calculator like https://www.color-contrast.dev/?txtColor=FFFFFF&bgColor=317C... to see WCAG-2-style "contrast ratio" metrics computed using APCA.)
The point of APCA is to make the contrast calculation more perceptually accurate, not just lower the threshold.
> The point of APCA is to make the contrast calculation more perceptually accurate, not just lower the threshold.
If you're unlucky enough to be familiar with the math, it is trivial to show it lowers the threshold at luminances, no matter the luminance (widely accepted Y or L*, or APCA's own luminance calc)
Re: the idea I think the point of APCA is to lower contrast threshold - you're entirely correct that this is a side effect of the main goal - to model contrast more accurately.
There is no such thing as non-perceptual contrast, perceptual contrast is a tell stuff is being regurgitated.
We're a bit far afield when we're doing APCA => BCPA => claims actually contrast ratio is 2.4 => look at actual contrast ratio, and its...5.39.
2.4 is supposed to be unreadable, which clearly isn't the case here.
So what's going on?
The wrong text size is being used on the BCPA site, it's being calculated as if it's 12 pt and it's 36 pt in the article.
No it doesn't? The screenshot of the calculator in the blog post very clearly shows that white has a greater contrast according to APCA. (If the negative numbers are confusing, you can also put the colors into a BridgePCA calculator like https://www.color-contrast.dev/?txtColor=FFFFFF&bgColor=317C... to see WCAG-2-style "contrast ratio" metrics computed using APCA.)
The point of APCA is to make the contrast calculation more perceptually accurate, not just lower the threshold.