Recently Ravelry was rebranded and the website redesigned to suit their new brand. Apart from meeting Google Lighthouse scores, it appears that accessibility was not considered as core to the redesign.
The Ravelry community are speaking out against the lack of inclusive design decisions and some people have been experiencing seizures when using the website.
The seizures appear to be triggered as part of the high contrast redesign colours and patterns, as Countess Ablaze describes:
"I suspect for me it was the glaring white, sensory overload of a lot of colours, flickering and high contrast black lines. I can't speculate anymore than this and now I've had one seizure (I've been seizure free since Nov 2018) I'm at higher risk for another."
I personally didn't know that high contrast ratios and patterns have the risk of causing physical reactions and seizures. As per WCAG 2.3.1 I knew that flashing content was wrong, but not in the sense that colours could be perceived to be flickering without any flickering mechanism of the website.
Reading further on seizures and physical reactions from the MDN docs, it's not just flashing animations, but patterns of light and dark straight lines. It gets quite mathametical and complicated!
As part of our advice in building better websites, I think we need to be aware of the too-high contrast boundaries. We already know the minimum contrast ratios as per WCAG success crition 1.4.3, but I don't think the maximum contrast ratios are clear. Is it just that it's too subjective? Or is success criterion 1.4.6 the gold-standard and maximum contrast ratio? Maybe these are too simple questions to solve a complex problem.
Would anyone know of other reading material on the subject?
Diclaimer: I am not a Ravelry member, but I have been watching discussions in the accessibility community and I'm taking notes on how not to rebrand.