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w3c / wcag

Web Content Accessibility Guidelines
https://w3c.github.io/wcag/guidelines/22/
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WCAG Example suggests "blurring" does not affect animation triggering vestibular motion perception (but it can) #3949

Open cookiecrook opened 1 week ago

cookiecrook commented 1 week ago

The definition of motion animation excludes "blurring", which appears incorrect to me. https://www.w3.org/TR/WCAG22/#dfn-motion-animation

motion animation addition of steps between conditions to create the illusion of movement or to give a sense of a smooth transition

EXAMPLE For example, an element which moves into place or changes size while appearing is considered to be animated. An element which appears instantly without transitioning is not using animation. Motion animation does not include changes of color, blurring, or opacity which do not change the perceived size, shape, or position of the element.

Blurring is commonly used to elicit a "depth of field" effect (simulating an artifact of the eye's iris or camera aperture)... The resulting illusion is one of animation depth changes (in the z index), which is known to be a common trigger for vestibular motion disorders.

I would suggest the word "blurring" be removed from this example text, or perhaps changed to "dissolving"??? Though keeping both dissolving and opacity may be redundant, so my preference is just to remove the word "blurring."

You might also add "or perceived distance/depth" to the last sentence too.

…which do not change the perceived size, shape, position, or distance/depth of the element to the viewer.

mraccess77 commented 1 week ago

Personally, blurred images give me an instant headache and I can't look at them. This included blurred background filters on people's video feeds. So, I'd be in favor of including blur as a problematic aspect.