Introduction to screen readers and screen magnifiers

Many of the questions I get when I talk about accessibility are centered on the assistive technology used by people with disablitites. And since the first (and unfortunately often the only) kind of disability people tend to think about as affecting the way you use the Web is vision impairment, the questions I get are almost always about screen readers.

To a lesser extent I get questions about screen magnifiers, which are mainly used by people who have some vision, but who are not completely blind.

Obviously I try to answer those questions as best I can, mainly by using VoiceOver, the built-in screen reader in my Mac, to browse the Web, and by using the zoom feature in Mac OS X.

But I’m not blind or vision impaired, so me showing how assistive technology used by people with vision impairments works doesn’t really reflect how such AT is used by the people who rely on it.

Instead, I believe the best way of explaining how people actually use AT is by watching experienced users. And that leads me to three great videos posted on the Yahoo! User Interface Blog:

  • In Introduction to Screen Readers, Yahoo! engineer Victor Tsaran talks about who will be likely to use a screen reader, how screen readers work, and how they can be used to interact with the computer desktop and to browse web sites.
  • In Introduction to Screen Magnifiers, Karo Caran shows how the screen magnifier ZoomText is used to make the computer desktop and web sites readable to people with reduced vision.
  • And finally, in From the Mouth of a Screenreader, Doug Geoffray from GW Micro (Window-Eyes vendor) talks about the history of screen reading software and how they analyse what is displayed on the screen in order to speak it to the user.

If you have never seen somebody use a screen reader or screen magnifier, or if you have but need a refresher, these videos are highly recommended.

One neat thing that I noticed about the videos posted on the YUI Theater is that you can either watch the videos in your browser or download them in MPEG-4 format and put them on your iPod. Perfect for those lazy summer days away from the computer ;-).

Posted on July 17, 2007 in Accessibility


  1. July 17, 2007 by Roger Johansson (Author comment)

    Just after publishing this I noticed that the YUI blog is down. It seems like there is a problem with their WordPress installation. I hope it’s a temporary problem and that the site will be back up soon.

  2. July 17, 2007 by Michael Hessling

    What about deafness? None of the YUI Theater videos have been captioned.

    Very unfortunate. And inaccessible to folks like me.

    (As far as I know, only Jeremy Keith and Vitamin have provided captions for their podcasts/videos.)

  3. July 17, 2007 by Andy

    On a Mac, hold down CTRL and scroll your mouse wheel/ball - instant screen zooming. For free.

    (I notice ZoomText is listed at $600 !)

  4. @Andy: you really can’t compare Mac’s CTRL+scroll zooming to the functionalty that ZoomText offers. Those are two entirely different worlds :)

  5. July 17, 2007 by Roger Johansson (Author comment)


    What about deafness? None of the YUI Theater videos have been captioned. Very unfortunate. And inaccessible to folks like me.

    Yes, that’s very unfortunate :-(. Captioned videos seem very rare, and I suspect it’s because of a combination of unawareness and lack of time. Not valid excuses though.


    Agreed, the built-in zoom in Mac OS X is very inferior to that in specialised products, but it’s better than having nothing.

  6. I like this article because:

    a) It’s always useful to have a well-considered post to refer to about screen readers (I’m sure I’m not alone in saying: I don’t know them ‘that’ well!) An introduction to assisting technologies is a great thing. Good one!

    b) It’s not about the iPhone.

    I’ll come back to this article later. Hey Roger - you’re meant to be spending your time with the new kid right? ;)

  7. At Webstock 2006 Darren Fittler gave an unforgettable presentation showing his problems using a screen reader on a site that was poorly designed, but that he uses daily in his work. For a real-life demo of using screen reader software I’d urge people to watch his presentation:

    It’s available in half a dozen formats of various file sizes.

    Darren was kind enough to reduce the speech speed so the sighted audience could keep up. :-)

  8. July 18, 2007 by Andy

    Well, the screen zooming in 10.4 does get blocky at high magnification, but when 10.5 arrives the screen zooming should be resolution independent - so the quality will equal or surpass ZoomText. The Text to Speech voices are getting a big improvement in Leopard too.

    Fortunately, I don’t need to make use of any of the accessibility functions - but I was under the impression that there were very good.

  9. Michael Hessling:

    What about deafness? None of the YUI Theater videos have been captioned.

    Very unfortunate. And inaccessible to folks like me.

    (As far as I know, only Jeremy Keith and Vitamin have provided captions for their podcasts/videos.)

    All of the SitePoint Videos have captioned versions for deaf users. Providing captions is a time-consuming and thus fairly expensive process, which is probably why they’re not more prevalent.

    Jeremy has experimented with using Casting Words, a service based on Amazon’s Mechanical Turk to provide transcripts for podcasts, but unfortunately, the results don’t seem to be quite there yet.

  10. Hey Roger,

    Thank you for pointing to the videos on our blog. We thought it was important and useful to make and publish these videos, because as much as most developers care about accessibility many have never had a chance to see most Assistive Technology in action.

    We hope/plan to expand our series on accessibility in the near future, so stay tuned.

    We did have a small hiccup on our blog, but things should be fine now. My username is nate and my domain is koechley dot com if you notice anything else amiss.

    Glad you like the MPEG-4 versions too :)

    thanks, nate

  11. Still getting the Wordpress error (“Error establishing a database connection”) for the three links above.

  12. The greatest impact of videos like this is in being able to demonstrate to people early in the learning process exactly why and how this software is used - and how their code can directly affect the ability of the software to produce meaningful output.

    While its only ever discussed in a purely theoretical environment its a bit hard for them to understand.

  13. July 24, 2007 by Dustin

    I wonder how Helen Keller surfed the net..

  14. July 24, 2007 by Roger Johansson (Author comment)

    Who is Helen Keller?

  15. July 24, 2007 by Sami

    I think he might be referring to her. According to the article, she was deafblind. Although I don’t think people were too worried about the web back in those days…

  16. > I wonder how Helen Keller surfed the net..

    > she was deafblind

    Some people who are both blind and deaf use a refreshable braille display. These devices have a row of tiny pins that go up and down to provide braille dynamically.

    Also, some people who are blind and can hear use a combination of the speech from the screen reader and the braille display. For example, someone might use speech most of the time, and then use the braille display while giving a presentation to know what’s being displayed or to check their notes.

  17. A book about Helen Keller was required reading in some grade of primary school in the United States at the time that I attended that grade. I caouldn’t give you details now, but I think reading about her has influenced my concern for accessibility on the web now.

  18. Thank you for bringing this topic to attention! I’ve always wondered why only partial visual impairments have been addressed when discussing web accessibility. I would love for someone to write a decent article on CSS2 Aural Style Sheets and their possible uses.

  19. This is an important topic, and I’m glad that designers are giving deep thought to it.

  20. Thanks for the links to the videos. Hopefully they will be able to shed some real light on the mysterious side of web accessibility and help me to evaluate if my techniques are actually working or if I could make a little more effort in that area.

    And I agree with Adrian, it would be really nice to have a decent article or two about aural CSS.

  21. July 30, 2007 by Roger Johansson (Author comment)

    Adrian, Joe: There are very few articles on aural CSS because it has very limited support in voice browsers and screen readers. Besides, I am not so sure it is a good idea to interfere with speech.

    Anyway, one of the most thorough articles I have seen on the subject is Jon Gibbins’ Aural CSS: Support for CSS 2 Aural Style Sheets / CSS 3 Speech Module.

  22. I use ZoomText. I will never again use another computer without it. Mainly what’s really useful other than the fact that it magnifies/reads the stuff to you is that there are keyboard shortcuts — I have a little over 200 memorised. JAWS and stuff for the blind have over 400.

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