Ann 🧡 (she/her)Does anyone have an article to recommend on *maximum* contrast ratios for readability of paragraph length text?
[Now answered, thanks!]
I think part of the answer for my max contrast issue question is not using FFF white on 000 black in dark mode, per this section of a CSS tricks article:
https://css-tricks.com/a-complete-guide-to-dark-mode-on-the-web/#aa-dark-mode-colors
Dark Mode in CSS Guide | CSS-Tricks
“Dark mode” is defined as a color scheme that uses light-colored text and other UI elements on a dark-colored background. Dark mode, dark theme, black mode, night mode… they all refer to and mean the same thing: a mostly-dark interface rather than a mostly-light interface.
David Kieffer@agvbergin I've never seen anyone talk about maximums in regards to accessibility. I think it's generally accepted that higher is better for people with differing vision abilities... so 21:1 (black on white) would be the highest contrast ratio you can have to allow the most amount of people to be able to read. But I'd be curious to learn if there's something that challenges traditional thinking.
Curtis Wilcox@dkieffer @agvbergin
Pure black and white can be too intense for some people. Especially light-on-dark can cause a vision effect called halation.
I don't have a good source to cite but I've heard one should try to avoid contrast above 18:1 or even 15:1 for your main text content.
https://accessibility.huit.harvard.edu/use-sufficient-color-contras
@cwilcox808 @agvbergin thanks for sharing; I learned a new word! You'd almost think the halation effect is related as much to the physical screen brightness as the digital contrast ratio.
@dkieffer
Yes, the brightness and contrast of the display device is an important factor. In many cases people for whom it's a problem can mitigate it by lowering the display brightness but some displays don't let you lower it enough.
I don't have this problem but I had a Dell monitor that was good but if I turned it on in the middle of the night it was too bright even at its lowest setting. TVs often don't let you lower the brightness much.
@cwilcox808 @dkieffer Thanks for this.
I have the halation problem (due to astigmatism) and an additional photosensitivity problem and my "feeling dazzled" issue happens close to 18:1.
I think it might be worse too when white is set to FFF, which thankfully isn't that common.
Myndex 🔵@agvbergin @cwilcox808 @dkieffer
Yes halation in dark mode can be an issue. But in order to set a max contrast, the contrast calculation has to be perceptually uniform. WCAG2 contrast is not accurate to use this way, and WCAG2 is also not useful for dark mode.
APCA can calculate for dark mode, and we are testing the following maximums (negative Lc value means light text/dark BG).
DARK MODE MAX
Small text (under 24px): Lc -90 max
Medium bold text (24-36px): Lc -85max
Large text (>36px) and thick solid icons or buttons: Lc -80
And Lc -75 max if the BG is darker than `#333333 `
We have a discussion thread on the subject at the APCA forum: https://github.com/Myndex/SAPC-APCA/discussions/106
