Adapting existing PDFs to accessibility standards
Accessibility is an important issue - also in the digital area.
Therefore, in all public institutions across the EU,
including universities,
Accessibility requirements are implemented,
to allow as many people as possible - with or without disabilities -
to have independent access to places and information.
Accessible PDF documents are an important part of this.
In this video we explain what accessible PDFs are
and how to check the accessibility of PDFs and adjust them if necessary.
Step 1: What are accessible PDF documents?
You probably know this from your work routine:
Existing PDF documents
do not meet the requirements of accessibility
and have to be adjusted.
This is especially important
when documents are to be made available long term.
But first: What are accessible PDF documents?
They can be recognized by technical aids
such as screen magnification software and screen readers
so people with visual impairment can read them independently.
They are clearly designed and structured
and have some technical specifications.
Step 2: Check PDFs for accessibility
To find out how accessible your PDF document is,
you should first do an automated check.
To do this, open your PDF in Adobe Acrobat Pro.
In the right column, select the "Accessibility" tab.
If this is not available, select the menu item "More Tools"
and then under the heading "Protect and Standardize" the item "Accessibility".
Now click on "Accessibility Check"
and select "Document" as category.
All boxes should be checked.
You can now start checking.
This will give you a complete overview of your document
and any potential problems.
You will also receive initial tips for troubleshooting.
Depending on how complex your document and the error messages are,
you now have various options for solving the problems:
Not all PDFs can have their accessibility
easily adjusted afterwards.
If when creating the original document
no attention was paid to accessibility
and for example many graphic design elements were used
or colors without sufficient contrast,
or when creating lists and tables
no Styles were used,
it is often next to impossible to subsequently make the document accessible.
Unfortunately, accessibility cannot always be fully reached.
But: every improvement helps!
If you still have the source file of your PDF
as a Microsoft Word file,
it makes sense to first make some adjustments in Word,
then export the document again as a PDF
and then finalize it in Adobe Acrobat.
However, if your document is only available as a scanned image
or the check revealed a lot of error messages,
but the original file is no longer available,
it is advisable to create the document
from scratch in Word and Adobe Acrobat,
instead of tormenting yourself with the subsequent, very time-consuming adjustment.
How to properly plan accessible documents right from the start,
create them in Microsoft Word and finalize them in Adobe Acrobat Pro,
is explained in the video tutorial "Accessible PDF Documents".
Step 3: Check PDFs for accessibility
If your document passes the Accessibility Check
without too many error messages,
you can improve your PDF directly in Adobe Acrobat.
Let's take a closer look at the Accessibility Checker report.
OK, there are some error messages.
But don't panic, we'll take care of those now.
First of all, some basic advice about the procedure:
Save your PDF under a new name after each step,
as some of the adjustments that have to be made
cannot be reversed.
Otherwise you would have to start all over
if you ever made a mistake.
First, add the missing document title.
To do this, open the “Properties” of the document under “File”.
Here you can add the so-called Metadata,
starting with the title.
You can also name an Author here.
For the screen reader to read the title of your presentation
when opening the document, rather than the file name,
select "Show" and "Document Title"
in the tab "Initial View".
Next we set the document language
in the "Advanced" tab.
This is important so that a screen reader knows
how to emphasize the text when reading it.
Because a text in a foreign language can quickly become incomprehensible
when pronounced with a German intonation.
How to assign a different language to individual paragraphs or words,
we'll explain later.
Then confirm with "OK"
and save the PDF under a new name.
The next error message tells us
that the PDF is not tagged.
We must fix this problem,
as tags are crucial for the functionality of accessible documents.
Only tagged PDFs
enable reading with a screen reader
as well as navigation within the document.
Tags define, for example, whether a text is a Heading or a Standard Text
or identify a graph or table as such.
Open the tag control panel in the bar on the left.
If this is not available, you can right-click
within the bar and add the menu item "Tags" in the bar.
We are reminded once again that there are no tags so far.
If Styles had been used when creating the document in Microsoft Word
tags would already be available.
Tags can be assigned automatically in Acrobat.
However, a bit of readjusting will still be necessary.
First click on the top menu item on the right hand side
"Autotag Document".
As you can see, tags are now in place.
The top tag always needs to be the tag,
which is still missing here.
Select "New Tag" in the menu at the top
and within the popup choose "Document" as Type.
Now assign all tags to this tag
by dragging them to the corresponding level.
In order to check the tags and adjust them if necessary,
open the "Reading Order" tool.
Here you can display the structure types.
What do we see? The heading is tagged as a normal paragraph .
But it should be a heading ,
which is assigned only once in a document, for the title.
Use the mouse to select the area of ​​the heading
and choose "Heading 1".
The tag has turned into .
You can now check the other tags.
The next heading should be tagged .
To do this, select the text area with the mouse
and then click on "Heading 2" in the "Reading Order" tool.
The following paragraph and the graph are already correctly tagged.
Now we define the next heading .
At the moment our list is still displayed as a paragraph.
Unfortunately the customization of lists
is not possible with the "Reading Order" tool,
it has to be done manually.
First you need to use tags to structure
the list by selecting the “List” tag.
Then create the sub-elements of the list.
To do this, create a new "List Item" type tag for each row.
and assign them hierarchically to the list tag.
The next required tag "List Item Body"
refers to the list text of the first row.
This in turn must be assigned to the tag,
by dragging it to the correct position.
We repeat the procedure for the second row.
The structure of the list is now finished.
Now you have to assign it the content.
To do this, split the existing paragraph
in two paragraphs with the Reading Order tool.
Now drag your two paragraphs into the list to the tag
The last element is a table.
For a table to be easily read by a screen reader,
the contents of the first row must always be tagged as
"Table Header Cells" with
In our case, this was already assigned correctly
during automatic tagging.
In the next two rows, the first
column is also tagged as a heading.
This is not correct.
We make the correction,
by right-clicking on the tag
and selecting the "Properties".
Here we change the tag type to "Table Data Cell".
A comment:
The more complex a table is,
the harder it is for a screen reader to interpret.
There are limits on how accessible
you can make it.
What we can do to optimize the readability some more
is the following:
We select the table tag
and right-click to open the Options Menu.
Here we open the Table Editor.
You can now assign the correct content
to each header cell.
In our case, each header cell relates to a column.
With a right click on the header cell
we open the "Table Cell Properties".
Under “Scope” we now select “Column”
and confirm with OK.
We do the same with the other two header cells.
The last step is to add
a machine-readable title to your table.
To do this, select the tag of your entire table
and open the Reading Order window once more.
Now select the entire table with the mouse
and right-click on the table to open the Options Menu.
Here you select "Edit Table Summary",
enter a descriptive title
and confirm with OK.
A note:
With some testing software,
for example the PAC 3-PDF Accessibility Checker
the row elements of tables are
identified as graphs that are not tagged.
However, adapting this would be beyond the scope.
The tables can be read easily using the method described here.
Therefore, you can safely ignore this error message.
The best thing to do is to save your document again under a new name,
before finalizing the PDF.
Let's check the accessibility again.
The next important error message concerns
the missing Alternate Text of our image.
In order to add the Alternate Text,
right click on "Figures Alternate Text"
and choose the option "Fix" in the error report.
The text can be entered here.
The structure of an Alternate Text should be as follows:
1. Illustration type (e.g. photo, line drawing, pie chart...),
2. a short description, as objective as possible
3. the copyright notice.
In general:
Use technical terms
and put any terms quoted from the illustration in quotation marks.
If your image is a purely decorative element
that does not convey any information,
you can also specify that,
by ticking the box "Decorative Figure".
In this case, your illustration does not need Alternate Ttext
and is skipped by the screen reader.
Almost all error messages have now been eliminated.
There is one very important check that you should make:
If the document was tagged manually with the Reading Order tool,
you should also check the reading direction of your document,
by opening the menu item “Order” in the left panel.
Each element now has a number.
This indicates the order of the objects within the document,
in which the screen reader will read them.
If structure types are being displayed instead of the numbers,
open the "Reading Order" tool once again
and switch here to "Page content order".
If an element is incorrectly positioned,
you can drag it to the desired position
while pressing the mouse button.
If you are happy with the order,
you can right-click on the error message
in the panel and select “Pass”.
Another error message that we have to correct manually,
is that of "color contrast".
Here we are asked to check
whether texts are easy to read on a colored background.
The lower the contrast between text and background color,
the harder it is to read,
especially for people with visual impairments.
In our case it should work.
In the Accessibility Checker area, confirm this by right-clicking
on the error message and clicking on "Pass".
There are no more error messages.
However, there are still little things
which do not appear in the test report,
but still improve readability enormously.
As already mentioned, a foreign-language text
read aloud by the screen reader with a German intonation
can quickly sound incomprehensible.
To prevent this,
we have already determined the correct document language.
But maybe your document contains
individual passages in another language?
We are adapting these now.
In the tag overview, select the text area
that is in another language.
Right-click for the Options Menu
and open the properties of the tag.
Here you can select the language.
A note:
You can only assign one language per tag.
In case your foreign language text belongs to
a longer paragraph,
you have to split the text into different tags.
Another helpful function for navigating the document,
is the bookmarks that can be found in the top left.
They show the document structure,
as it is set for the visually impaired.
This is particularly important for multi-page documents
with a chapter structure.
Bookmarks allow users to navigate through a document,
without having to flip from page to page.
In our case there are no bookmarks yet.
However, after having clearly structured
our document with the help of tags,
we can select the command "New Bookmarks from Structure".
Here we see how the document is structured
and can choose
which elements should be part of the table of contents.
It makes sense to only use the headings here by selecting
them while pressing the shift key and confirming.
Here, too, the headings can be hierarchized afterwards,
so that the document's logic of headings
and sub-headings is reproduced correctly.
Now it's almost done.
In a last step you only have to set the PDF / UA identifier.
Because for a PDF to be considered technically accessible,
the meta information must be available,
which marks the document as PDF/UA compatible.
Open “Print Production” on the right and select the “Preflight” option.
Select the wrench in the preflight window.
Under "Document info and Metadata"
you will see the menu item "Set PDF/UA entry".
Select this and click on "Fix" at the bottom right.
You can now save the final PDF.
Summary
I will briefly summarize again
What to look out for when adapting an accessible PDF.
First you define the Metadata such as title or language.
Then tag your document
and add Alternate Text to images and graphs.
Check the reading order and color contrasts,
bookmark your document
and set the PDF/UA identifier.
In between you save your document
again and again under a new title,
so that in the worst case you don't have to start all over again.
If you do run into technical difficulties,
please feel free to contact the
Center for Information Technology and Media Management