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Re: Character limit on alt-text in PDF?


From: Chagnon | PubCom
Date: Jun 28, 2013 2:03PM

RE: Alt-text length. I was advised long about to keep it under 200
characters. Can't even begin to find where that recommendation came from.

RE: long descriptions in PDFs, this question has been asked a few times on
this list and never, in my opinion, satisfactorily answered.

WCAG doesn't acknowledge that PDFs exist. <grin>

We've developed some solutions that we think meet the intent of WCAG 2.0,
based on what WAI technique 1.1.1 recommends for websites

1) For graphical charts and other graphics that illustrate statistical data:

- If the source document is available, add a table below the graphical chart
that contains the same data. We've found that our AT testers prefer this
solution because it gives them direct access to the data.

- If you can't change the source document but are stuck working with just
the PDF, add a blank page at the end of the PDF and put the table there. In
some cases, it can be helpful to also have a paragraph of text to describe
or analyze the data, what a LONGDESC would do. Hyperlink from the graphic to
the back page, and then hyperlink a return to the original page. Messy to
create, but it works fine for AT-users.

2) For other situations:

- If you can edit the original source document, work a narrative description
into the body text that describes the graphic's data. Something like "in the
bar chart below, sales increased to $2,000 in May, a 100% increase from
April which were $1,000."

- If you can't, the "back of the PDF" method above will work for this, too.

-Bevi Chagnon
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-----Original Message-----
[mailto: <EMAIL REMOVED> ] On Behalf Of McMorland,
Sent: Friday, June 28, 2013 2:43 PM
Subject: [WebAIM] Character limit on alt-text in PDF?

Is there a character limit on the alt-text for images in PDFs?
If not, then how long is too long?

Also, where do you usually put long descriptions for complex images in PDFs
hosted on a website? If it was HTML I could use longdesc, but I'm not sure
where to put them with the PDFs used in our online courses.

Thanks for your thoughts,
messages to <EMAIL REMOVED>