Re: Flash index problem.

Hi All,
I brought this up because it bothers me.

Here is the problem. When you read and listen at the same time, you keep
your visual focus on the word being read. The visual information
reinforces what you cannot hear, and the audio reinforces what you cannot
see.  So, unlike non-visual access to reading, other people with print
disabilities use the see/hear combination to boost comprehension. This
requires looking at the word being read.

The word highlighted appears at the same region in the visual field. It
looks like a flash. I have tried not looking at the highlighted word, but
that disrupts comprehension.

As far as slowing down reading speed to below 180 wpm, that works but
reading drags. The typical person reads  200-250 words per minute on
average.

Good ebook or article readers give the user a choice to highlight:

   - None,
   - Word,
   - Phrase or
   - Line.

I brought this up because I observed the problem, and could calculate that
it does not meet Web guidelines. That means it may be an accessibility
issue. Log it. You may not be able to address it, but it is a potential
problem.

I did not start with the numbers and go backwards. I started with
persistent nausea and worked backwards.

At CSU Long Beach we had a lattice lath structure over a sidewalk that
caused flash issues for people who walked under it. We discovered it when
the vice president of publications got extremely dizzy whenever she walked
under it at lunch time. She was a member of our Accessible Technology
Initiative, and recognized the issue. The University changed the
orientation of the lath and the problem went away. That is not a Web
problem, but the Web guidelines enabled us to identify the problem. When a
person walked under the lath at a normal speed it created a flash effect
that was greater than 3/second.

This highlight flash may not be a web content issue, but it may very well
be an IT accessibility issue.

Best, Wayne








On Wed, Aug 25, 2021 at 8:51 AM Janina Sajka <janina@rednote.net> wrote:

> Good points, John.
>
> In terms of mitigation -- APA is looking at a technological solution.
> We're expecting a presentation of tech developed at MIT at an upcoming
> RQTF call. The concept has been proven to work. Now we need to get the
> licensing and user agent adoption.
>
> John Foliot writes:
> > Hi Janina,
> >
> > Not sure if you are aware of the PEAT testing tool from the Trace Center
> (
> > https://trace.umd.edu/peat/), however they state:
> >
> > "In general, web or computer content will not provoke seizures if either
> of
> > the following is true:
> >
> >    - There are no more than three general flashes and no more than three
> red
> >    flashes within any one-second period, or
> >    - The combined area of flashes occurring concurrently occupies no more
> >    than a total of one quarter of any 341 x 256 pixel rectangle anywhere
> on
> >    the displayed screen area when the content is viewed at 1024 by 768
> pixels.
> >    "
> >
> > So my reading between the lines suggests that it's less the location, and
> > more the size. I wonder aloud how this is applicable to Wayne's
> > concern/observation?
> >
> > As a TTS tool that also provides text highlighting processes the
> individual
> > words it is reading, are those 'highlighted words' less than or greater
> > than "...a total of one quarter of any 341 X 256 pixel rectangle"? Or is
> it
> > more looking at a combination of "flashing highlighting" that is also
> > introducing horizontal movement (L to R in English, but R to L in, say
> > Hebrew) that it then becomes a concern? (In other words, while each word
> is
> > highlighted individually, and thus likely below the individual
> measurement
> > thresh-hold, is the *proper* way to evaluate this to instead think of
> this
> > as the block of text that is flashing or strobing in the aggregate?)
> > Perhaps an issue that requires clarification and review in WCAG 3?
> >
> > Nonetheless, while I recognize the issue and concern, I'm also not sure
> > there is anything an individual content author can do to mitigate or
> > remediate this edge-case scenario.
> >
> > JF
> >
> > On Wed, Aug 25, 2021 at 8:51 AM Janina Sajka <janina@rednote.net> wrote:
> >
> > > There's an additional nuance I've not previously considered ...
> > >
> > > Is the flash sensitivity specific to location on screen? i.e. more than
> > > 3 per second at the same x,y location?
> > >
> > > Or does successive highlighting of words on screen also trigger the
> > > hazzard?
> > >
> > > To me this seems like it would be worth clarifying.
> > >
> > > Best,
> > >
> > > Janina
> > >
> > > John Foliot writes:
> > > > Hi Wayne,
> > > >
> > > > Ah, math <smile>. This presumes that the end-user has configured
> their
> > > TTS
> > > > engine to read at this speed - but since all screen readers I've seen
> > > also
> > > > allow the end-user the ability to adjust the reading rate, this by
> > > > extension means they can also adjust "flashing" in the use-case
> context
> > > you
> > > > provided. (And if the user-agent stack doesn't, this is a failure of
> > > UAAG,
> > > > which is non-normative, sadly.)
> > > >
> > > > Additionally, this will manifest on *any* content rendered in the
> > > > user-agent - this cannot be mitigated by the individual content
> > > > author/owner - it is a concern rooted at the user-agent level.
> > > >
> > > > One has to presume that a user who both requires
> > > > text-to-speech+highlighting AND is also sensitive to flashing content
> > > will
> > > > have previously adjusted their user-agent stack to address this
> issue.
> > > >
> > > > JF
> > > >
> > > > On Tue, Aug 24, 2021 at 6:57 PM Wayne Dick <wayneedick@gmail.com>
> wrote:
> > > >
> > > > > If you are reading with a text-to-speech reader and it highlights
> > > words at
> > > > > more than 180 words per minute, then you have more than 3 flashes
> per
> > > > > second.
> > > > >
> > > > >
> > > >
> > > > --
> > > > *John Foliot* |
> > > > Senior Industry Specialist, Digital Accessibility |
> > > > W3C Accessibility Standards Contributor |
> > > >
> > > > "I made this so long because I did not have time to make it
> shorter." -
> > > > Pascal "links go places, buttons do things"
> > >
> > > --
> > >
> > > Janina Sajka
> > > https://linkedin.com/in/jsajka
> > >
> > > Linux Foundation Fellow
> > > Executive Chair, Accessibility Workgroup:       http://a11y.org
> > >
> > > The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
> > > Co-Chair, Accessible Platform Architectures
> http://www.w3.org/wai/apa
> > >
> > >
> >
> > --
> > *John Foliot* |
> > Senior Industry Specialist, Digital Accessibility |
> > W3C Accessibility Standards Contributor |
> >
> > "I made this so long because I did not have time to make it shorter." -
> > Pascal "links go places, buttons do things"
>
> --
>
> Janina Sajka
> https://linkedin.com/in/jsajka
>
> Linux Foundation Fellow
> Executive Chair, Accessibility Workgroup:       http://a11y.org
>
> The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
> Co-Chair, Accessible Platform Architectures     http://www.w3.org/wai/apa
>
>