Creating accessible PDFs from LibreOffice Writer

Before starting

Make sure that your version of LibreOffice is Version 7 or above – check by going Help -> About LibreOffice, or if not installed, download LibreOffice (external website)
Older versions may require the tool to be turned on as an Advanced option (“Enable experimental features (may be unstable)”) but it is inbuilt in more recent versions
Make sure that Adobe Acrobat Pro is up-to-date
Download PAC 2024 (external website)

Demo file

An example file, LibreOffice-un-accessible.odt (ODT 164KB), has been created which has issues that need to be corrected.

Making documents correctly

Title, Author etc.

While Title is the only field that is required in an accessible PDF, it is worth adding Keywords for SEO, adding the Subject, and a generic Contributor and a Publisher. If you do not wish the name of the real author all over the internet, replace them with organisation name.

Headings

Use the headings built into LibreOffice Writer
The page content should be outlined in the headings, which helps AT users comprehend the page layout and navigate to interesting content:
- Main heading = Heading 1
- Sub-headings = Heading 2
- Sub-sub-headings = Heading 3 etc.

Lists

Use the inbuilt document list controls within LibreOffice Writer to add ordered lists (numbers) and unordered lists (bullet points)
AT users can understand lists created as lists because of the way content is organised
Lists will communicate helpful information such as:
- How many items the list has
- Where the list starts and where the list finishes
- Which list item the user is on

Hyperlinks

The destination of links should be communicated accurately and clearly
Use URL shortening services such as Bitly (external website) or TinyURL (external website) if the document is to be printed, if not, make sure the link text is meaningful (link shorteners can be viewed as a security risk as the destination cannot be seen unless the link has been clicked!)
Screen readers will generally provide a list of links so make sure the link text is meaningful
Do not use “click here” or “More information” for all the link text because it will not be possible to distinguish the links from each other

Alternative text for images (alt text)

Alt text is used to convey the content of the image to those who can’t see it
Screen readers will declare the image, then read the alt text
Images that have no informative content and are purely decorative do not require alt text, but may require markup so that Assistive Technology understands that they should be ignored
Remember to avoid punctuation as it is voiced
MakeThingsAccessible has a guide to creating meaningful alternative text

Image use

Only use images that support the text of the document
Try avoiding the use of an image instead of text
Make sure images have alt text unless they are decorative

Language

Leading screen reader software is multilingual.

Language of document

The language of the document must be set so that screen readers will read the document using the correct language profile.

Language of part of document

Content within the document written in a different language to the document’s default language must be identified.

Tables

Do not use tables to control layout
Use tables to communicate relationships between data
Make sure headers are identified
Try to keep the table simple
If the table is complicated, can it be split into multiple tables or into lists?

Other things to take into account for accessibility

Plain English

Make sure sentences are short and concise, around 20-25 words
Make sure words are kept simple
Use common words. Complicated longer words (8 or 9 letters) will cause readers to skip shorter words (3,4, or 5 letters) that follow
Use an Active voice rather than a Passive voice
Where possible, use words containing one to two syllables
Aim the language used at the level of a 9 year old as recommended by GOV.UK (external website) – remember in the UK, 7.1 million adults read at, or below, the level of an average 9 year old. WCAG 3.15 Reading Level (AAA) (external website) recommends providing a simplified version of the text if it requires a reading age of more than 12 years old
Use contractions, words made up of two short words joined with an apostrophe such as I’ve, can’t etc.
Do not use double negatives
Explain the unusual, to help give full information

Why use it?

The use of Plain English helps all users, including those who’s English is not their main language, and those who have cognitive impairment
If the content is easy to read, it will be easy to understand when converted into alternative formats such as braille, or being read aloud by a screen reader
Clear content converts more easily into British Sign Language

Further help

Free services, guides, and resources to help are available from the Plain English Campaign (external website)
Measure the readability of the text using Hemingway Editor (external website)

Font

Use a font that is “sans-serif” and clear such as Arial, Helvetica, or Verdana
Minimum font-size of 12
For continuous text, avoid using capitals - letters in lowercase are read more easily
Do not use underlining and italics because they could make text harder to read
Bold and large font can be helpful when emphasising and highlighting text
Make sure that text is justified to the left, as this helps to make sure there is an even gap between words, and enables the start and end of each line to be found easily

Colour

Do NOT use colour by itself to show meaning
Make sure that there is adequate contrast between background and text – use TPGi’s Colour Contrast Analyzer (CCA) (external website) to check contrast

LibreOffice Accessibility Check

Accessibility Check (external website) tests LibreOffice Writer documents for the following potential accessibility issues:

Check that the document title is set
Check that the document language is set, or that all styles that are in use, have the language set
Check all images, graphics, OLE objects for the alt (or title in some objects) text
Check that tables do not include split or merged cells, which could be disorienting for users with visual impairments
Check for fake/manual numbering (not using integrated numbering). For example writing "1." "2." "3." at the beginning of the paragraphs
Check that hyperlink text is not a hyperlink itself - hyperlink should be described
Check for the contrast between text and the background. The algorithm is described in the WCAG specification
Check for blinking text, which can be problematic for people with cognitive disabilities or photosensitive epilepsy
Check for footnotes and endnotes, which should be avoided
Check for heading order. Order of the headings must increase incrementally with no skips (for example Heading 1 to Heading 3, skipping Heading 2)
Check, if text conveys additional meaning with (direct) formatting

Running the Accessibility Check

Tools menu -> Accessibility Check… (or Alt + 8)
The errors reported are:
- Document: Document default language is not set
- Document: Document title not set
- Missing alternative or description text: 3 images
- Table: “Table1” contains merges or splits
- Formatting: The text formatting conveys additional meaning (58)
- Formatting: Avoid newlines to create space (3)
- Formatting: Avoid using empty table cells for formatting
- Hyperlink: Hyperlink text is the same as the link address
- Numbering: Simulated numbering “1. 2….”
- Other: Avoid footnotes (2)
- Other: Avoid endnotes
- Other: Outline levels should start with level 1, instead of level 2
- Other: Outline levels of headings not in sequential order
- Other: A heading with outline level 4 must not follow a heading with outline level 2
- Other: Text contrast is too low
- Other Blinking text

Fixing the issues

Note: sometimes you may need to save and close and reopen the document to get the Accessibility Check to recognise that you have fixed the error.

Language

Language of document

Click on the
by “Document default language is not set” or Tools menu -> Options, Languages and Locales -> General
Tools -> Options, Language -> For All Text -> language required

Language of part of document

Select text that is of a different language to the main document
Tools -> Language -> For Selection (or For Paragraph, as applicable) -> language required

Title

The error reported is “Document title not set” as this is a required field for accessibility.

Click on the
by “Document title is not set”
Go to File menu -> Properties… and then Description tab
Copy the contents of the Title into the Subject field
Add applicable SEO keywords into Keywords field
Add Contributor
Add Publisher

Alt text

The error reported is “Missing alternative or description text” because the images do not have alt text set or are not marked as decorative.

Click on the
by “Image name”
The fields are used as follows:
- Text: used to enter a short description of the essential details of the selected object, and is available to be used by assistive technologies
- Alt Text: allows the entry of a longer description for objects that are too complex or contain too much detail to be described adequately in the short Text field, and is available to be used by assistive technologies
- Decorative: marks the object as purely decorative and is ignored by assistive technologies
The Text Alternative (Text), Description (Alt Text), and Decorative options are also available by selecting the image, Right Click -> Properties, Options, Accessibility
The exported PDF failed on the logo in the Header not having alt-text so make sure that both Text Alternative and Description fields are filled

Tables

Setting headings in tables

Inserting a table

Table menu -> Insert Table
Insert table dialog box with column and row fields, options, including setting Heading, and Repeat heading rows on new page as well as setting the table styles
Checking the Heading means that the top row cells are now styled as Table Heading
If the table is going to go more than one page, select “Repeat heading rows on new pages” or select “Don’t split table over pages” to stop this from happening

Editing a table

Styles menu -> Manage Styles which brings up the Style pane
Select top row of cells and change Styles from “Table Contents” to “Table Heading”

Repeating heading when table splits across pages

Right click on table and choose Table Properties, Text Flow tab and make sure that “Allow the table to split across pages and columns”, “Allow row to break across pages and columns”, and “Repeat heading” are checked

Allow the table to split across pages and columns, allow row to break across pages and columns, and repeat heading are checked

Fixing errors

Table1” contains merges or splits

The first error being reported is “Table: “Table1” contains merges or splits”

Single complex table with females and males

This problem can be sorted out by splitting the table into two tables, one for females and one for males, and Table Heading added to columns and rows
This problem can also be sorted out in the exported PDF using Adobe Acrobat Pro

The text formatting conveys additional meaning

The second error being reported is “Formatting: The text formatting conveys additional meaning”

7:32 showing as the text formatting conveys additional meaning

To fix this error, set the text to Body Text
Then set the times back to the Table Contents style

Avoid newlines to create space

Make sure that “Formatting Marks” are visible by selecting View menu, Formatting Marks (or Ctrl + F10)
Delete the newline character after the table
To change space between the tables, open Table Properties, go to Table tab and amend the Spacing Below

Tables separated using table spacing properties

Avoid using empty table cells for formatting

Tables with empty cells

There must never be blank heading cells so add an applicable title to the column heading even if WCAG does allow for the first cell A1 to be blank (external website)
Different screen readers will announce empty cells in different ways (external website) so the best solutions are to use “Not applicable” or “No value”