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Usability for Moderate Low Vision

Wayne Dick
Registered: Dec 1 2009
Posts: 2

My question is this: Suppose I'm reading well structured tagged PDF. how can I change the Font style, the letter, word and line spacing, and font sizing at the document element level (tag level). The modifications are really necessary for
moderate low vision.

People like me with moderate low vision don't seem to be able to get a format we need. That disability group consists of individuals with visual acuity of
(20/70-20/160). It is protect by 504,
508 and the ADA.

Most of us don't use screen readers
unless that is the only option, and the
page modifications provided by zoom
technologies are to disruptive to the
page flow. The best accommodation is a restructured typography that may or may not be accompanied by text-to-speech.

Does anyone know how this disability
group can be served with PDF? These
changes are easily obtained with doc,
docx, rtf and odt as well as HTML and
other w3c markup languages.

I don't need advice about which
assistive technologies to use. I'm 60. My disability is life long. I am a
computer science professor and I've
tried every major assistive technology.
I haven't one process that is deterministic and will give me the typographic changes I need for effective reading PDF.

Please contact me with any techniques
(that don't involve AI).

You may contact me directly
wed [at] caulb [dot] edu or reply on the list.

Wayne Dick

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My Product Information:
Reader 9.2, Windows
daka630
Expert
Registered: Mar 1 2007
Posts: 1420
Bon dias Wayne,

Given that the PDF is well tagged then to address, in the PDF, what you have mentioned would call for editing to the page dictionaries.
In my opionion, not worth the candle.
Better that issues associated with font style, font size, white space above/below, spread, kerning, etc. be addressed by the content author.
Layout and format considerations really need to be addressed upfront.
Being a page description language, PDF is not where these issues should be addressed.

The prospect of performing manual edits to a page dictionary, with Acrobat Pro, brings to mind the song "can't get no satisfaction".

Based on what you posted, I suspect you are very well familiar with reflow, magnification and high contrast for PDF.
I suspect these are not "cutting it" for you.

At least two of the three applications that currently have means of tag management permit the content author to
single-source content then provide an "optimized" version (akin to large print books).
Tagged output PDF could come from both of these authoring files.
(The two applications I allude to are FrameMaker and Word. FrameMaker does better. InDesign may perform this too. Not a user, so I cannot speak to specifics of InDesign.)

Of course, what would be needed is a consensus of what is "optimal" for low vision end-users with regards to font type, size, spacing, and other layout/format aspects. This presumes that the accepted "norms" are not, in fact, adequate for the majority of end-users.

That you have to post process other file formats to obtain effective usability is unfortunate.
Certainly text edit formats like docx and rtf lend themselves to post processing with a word processor.
However, markup languages (SGML, XML, HTML, markup language present in PDF) do not; particularly when stylesheets are added to the stew.

Seems to validate that, for PDF (and other formats) the lowest common denominator for accessible/not accessible is the content author.

Just a closing observation.
The level of granularity associated with font size, font style, spacing, etc. certainly play to how usable an individual user may find a well tagged PDF to be; however, these variables are not spoken to in Section 508, WCAG 1.0 or WCAG 2.0.

While the "recommended" font types for "on line" information is a manageable population, there is a noted divergence of opinion as to which are the "best" few to use.
Having invested considerable time with search engines crawling dot GOV and dot EDU sites for information related to accessbile PDF I confess to disappointment with what is provided. Too often it is stale, somewhat "off" or presented with "spin" that is not factually based.
(File "types" are easy targets - no push back, content authors are something else, eh?)
Thus, "consensus" guidance (perhaps via NFB) becomes all the more important.

Be well...
[Edit :: 2009 12 27]
Over at WebAim. Related threads of discussion. Informative.

[url=http://webaim.org/discussion/mail_thread.php?thread=4042]Thread 1[/url]

[url=http://webaim.org/discussion/mail_thread.php?thread=4045]Thread 2[/url]

[url=http://webaim.org/discussion/mail_thread.php?thread=4039]Thread 3[/url]

[url=http://webaim.org/discussion/mail_thread.php?thread=4054]Thread 4[/url]

And at the FEDSTATS GOV site
[url]http://www.fedstats.gov/policy/publications/fedstats_wp1.php[/url]
some information that puts accessibility of any file format in perspective.
Older data; but, it puts a good focus on issues that are still with us.

Be well...