[scribus] New for 1.6.0 - Tagged PDF to improve accessibility of PDFs?
Matthias Schmitt
freak002 at mmp.lu
Sun Sep 15 16:15:31 UTC 2013
Hello Greg,
> Does anyone have feedback from the visually impaired that we can
> understand in terms of how to make some published material more accessible?
In principle its all about two criteria: text and structure.
1. Most important is the access to text based data. We all know the bad PDFs created by some free scanner software. They wrap the scanned image into a PDF and that's it. It is obvious, that the image is useless to visual disabled users. (Of course Scribus does always use text when creating PDFs if possible.)
So first and most important rule: everything must be text!
2. Accessibility in PDFs is not so different from Web accessibility. Example: images on the Web. They should have alternative texts, which make them accessible to the blind. Compare the alternatives read by a screen reader to a blind person: "image2375362.jpg" or "Photo: my favorite pop star and me on stage". Which one gives you more information? PDFs offer the possibility to embed alternative tests in PDFs, which are read by screen readers.
Remark: in case somebody stores multimedia data like sound files or movies inside a PDF, please do not forget to add a text transcript of the spoken words for the hearing disabled. Its not only about persons with visual disabilities.
3. Imagine a document with hundreds of pages. If a specific chapter is of interest you use the table of content to navigate directly to this chapter. PDFs have the possibility to create a table of content in the form of bookmarks. Some PDFs readers show them at the side of the content window. This useful for visual disabled and seeing people.
4. Imagine a multi-column layout with several boxes adding additional information blocks in the text. Some PDFs have a broken reading sequence. A visual disabled user will read the first line of the first column, then the first line of the second column, continuing with the second line of the first column, followed by the second line of the second column. So the sequence of the information is totally destroyed. A printer does not care about it.
There are more accessibility criteria, e.g. meta-information, correct tables, sufficient color contrast, initial view, tab order, etc. With the examples above I wanted to give you just a basic idea.
Best regards
Matthias
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