From Adobe InDesign to PDF
[Narrator:] Adobe InDesign is a commercial desktop publishing software developed by Adobe Systems. The software can be used for print or digital publishing to create documents such as posters, brochures, magazines, newspapers, books, e-books and interactive PDFs. Its primary target groups are graphic designers and desktop publishers. InDesign has native support for creating PDF documents. In fact, as PDF was invented by Adobe, it is the most powerful tool for creating accessible PDFs on the market. Please note that this is not an InDesign course.
We assume that you have basic knowledge of how to use InDesign. This chapter focuses on how to improve the accessibility of your documents. It will not explain how to layout, design or print documents.
So let's see how we can create accessible PDFs with Adobe InDesign.
Preparation
Before we start using InDesign itself, we need to think for a moment about the images that we want to include in our InDesign documents. Images in accessible PDFs require alternative texts. Alternative texts can be stored in the form of metadata inside the image file. If the alternative description of the image is stored as part of the image, we can reuse this description in many other documents without retyping the alternative text. When we copy an image, its alternative description will be copied as part of the image file as well. So let's see how we can add an alternative text to an image file. There are many programs on the market that can modify the metadata of image files. For our example, we will use Adobe Bridge as it is included as part of Adobe's Creative Cloud program suite. After starting Bridge, the program opens a file browser for us. We can use the file browser to select the file in which we want to add the alternative text.
The program now opens a preview of the image. On the right-hand side we see the metadata of the file. Some metadata attribute values cannot be changed without modifying the image, such as file format, creation date or resolution. Other metadata add additional information to the file without modifying the image itself. Bridge indicates editable metadata attribute fields with a little pen on the right-hand side. Metadata attributes are collected in different sets, such as File Properties, IPTC Core, IPTC Extension, Camera EXIF data and so on. Each set is defined by different standards or media types. For our needs, we will have a closer look at the IPTC Core attributes to edit the Headline, Description, or Title. InDesign will be able to access any of these attribute values to add their content as alternative text. For our purpose it is sufficient to add a description to the image. We type "Alice, the Rabbit and the Mad Hatter at the tea party". To apply and save our modification, we click the little checkmark in the lower right-hand corner of the Metadata pane. From now on the alternative text will travel with the image file wherever we move or copy it.
Pros and cons of metadata in images
A pro is that the alternative text becomes part of your image files. Whenever the file is copied or moved, the metadata travels with it. The alternative text can be reused in multiple documents. All images can be searched for using the description text in the metadata, which can be extremely useful when handling a large number of images. If the alternative text is updated, the update is automatically inherited by all documents referring to it. As a con, or at least a limitation, we have to assert that metadata is limited to one language.
Text styles
It is time to start InDesign and open our example document. We can see that this document contains information like headings, which present the structure of our document. The text uses links, which can guide the user to a website. We can see images, which need alternative text. Furthermore, we can see a list and a table. Beyond this, there is a complementary information block, which offers more information about the author of this document.
First we bring structure to our document using the headings. We open the Paragraph Styles panel via Window, Styles, Paragraph Styles. All texts are associated with a style. This is the first heading and, therefore, a heading of level 1. For a new document, we have the Basic Paragraph style. For our heading, we create a new style and name it “Heading Level 1”. As we know that this text style should be exported as a heading of level 1, we can immediately define this using the Export Tagging options. Under PDF Tag, we assign the H1 tag for a heading of level 1. Although we named our style “Heading Level 1”, we could have chosen any name. It is important to assign a style to a tag of the correct level. This looks like a heading of level 2, so we create a style “Heading level 2”. This looks like another heading of level 2, so we can reapply the newly created style. We assume that these are headings of level 3. Each heading is marked with its own style, named in a way so that we can identify its appropriate heading level.
You can use multiple different styles describing the same heading level. In the complementary information block, we create another style, which we will export as a heading level 1, but it has a completely different visual appearance. There can be multiple styles, each one being exported as a heading level 1.
If you have an existing document, there is no need to open each paragraph style and assign the PDF tag individually. You can edit all export tags at once. To do this, go into the Paragraph Styles panel and select Edit All Export Tags. Activate the PDF option. Now you can see all your styles and their tag assignments. If you want to modify a tag assignment, use the pop-up to select the appropriate tag value.
Lists
You can easily create lists in InDesign. Select the text lines you want to convert to a list and select Type, Bulleted and Numbered Lists, Apply Bullets. You can also create a Numbered list. Lists will be identified automatically by a screen reader as a list and presented as such to the user. You can nest numbered lists of different levels. Unfortunately bulleted lists cannot be nested in InDesign.
Tables
In InDesign you can easily create and modify tables. Obviously, the first row of our example table is a table header, which describes the type of content in all our table data cells below. Table headers will be recognised by screen readers and presented as such to the user. To activate table headers and/or footers, select Table, Table Options, Headers and Footers, or simply Convert Row to Header.
Here you will find a rich set of options to modify your table layout and table styles.
One remark related to tables: Tables should be used for table-based data only. You should never use tables for layout purposes. As an example, some people misuse tables to create a multi-column text layout. This should never be done. Use the InDesign functions designed to create a multi-column layout.
Bookmarks
The easiest way to create bookmarks is via the table of contents. To create a table of contents, select Layout, Table of Contents. The modal dialog box opens. Now add the heading styles that should be used for creating the table of contents in the correct order. Typically the lines in the table of contents do not use the same styles as the originating headings. Select the new style here.
Do not forget to activate the Create PDF Bookmarks checkbox. For our example, we do not want the table of contents to be part of the visible content. We just want to have the bookmarks. Therefore, we position the table of contents outside of any page area. Converting headings to a table of contents is an easy way to create bookmarks. You might prefer to create bookmarks manually. In this case, select Window, Interactive, Bookmarks. The bookmarks panel will open. Select the content you want to be marked and choose the Create new bookmark button from the bookmarks panel.
Hyperlinks
This text here looks like a Web link. We select the link text to create a clickable hyperlink for the user. Using a right mouse button click, we open the context sensitive menu and select New Hyperlink. We enter the Web address. Under the Accessibility tab, an alternative text can be added. Now confirm your selection with OK. Once exported to PDF, this link will be clickable for the user.
Images
Here we see an image that needs an alternative text, so that a screen reader can offer a user with visual disabilities a message describing the content of the image. Use the right-mouse button to open the context-sensitive menu and select Object Export Options… Select the Alt Text tab. From the Alt Text Source pop-up, select the source of the alternative text.
In a previous section we saw how to add metadata to an image including the title, description or headline. We can now select which of the attribute values we would like to use as the source of the alternative text.
If you do not want to use an alternative text from the metadata of the image, just select Custom and type your text. We have added an alternative text to our image, but when should the text be spoken? The image needs to be anchored inside the text so the screen reader knows when to speak the alternative text. To anchor an image in the text, use the anchor icon of the image frame. Click the anchor icon and hold the mouse button. Now drag the anchor while still holding the mouse to the target text position. Lift your finger from the mouse button when you reach the target position. The image is now anchored to the text. Choose the text position that is the most appropriate for the content of the image. InDesign allows you to anchor an image anywhere in the text, even in the middle of a word. To see the position of the anchors, select View, Extras, Show Text Threads. The dashed line indicates the connection between the image and the text position.
If you want to hide your image from being read by a screen reader, because it is a design element without content, then you should mark this image as artifact. To do this select the Tagged PDF tab and apply the Artifact tag. Now this image will be ignored by a screen reader. You can use the same mechanism to hide text frames from screen readers too. When we look closer at the Tagged PDF tab in the Object Export Option panel, we can see that this panel offers an additional possibility to enter text. We can enter an Actual Text. So what is the difference between Alternative Text and Actual Text? Imagine the name Alice using a nice graphic for the starting letter A. So we have a graphic A and the text “lice”. A screen reader could now say: “Image: letter A, lice” using the alternative text or it could use an Actual text, which replaces the image, to pronounce “Alice” without announcing the type of element. This is useful whenever an element contains a graphic of a text. Not every screen reader will be able to handle actual text presentations. If you have a text graphic, then fill in both options to be sure it can be handled by any screen reader.
Reading order
The document needs a reading sequence so a screen reader can speak the different elements in the correct order. To define a reading sequence, open the Articles pane. Select Window, Articles. Now drag and drop the single frames into the article page in the sequence in which they should be spoken. For our example, we decide that the text describing the author should be spoken at the beginning of the document, so that it does not interrupt the storytelling of the novel.
One very important detail is that even though you defined a reading sequence using the articles pane, InDesign will ignore it unless you activate the pane menu item Use for tagging order in tagged PDF.
Metadata
Accessible PDFs should have meta information, which helps the user to get an idea of what content to expect from your document. To enter the meta information, select File, File Info. A dialogue box will open, in which you can enter the Document title, the Author, a short Description, and some Keywords. Please note that meta information can only be entered using one language per document.
Export
To save your file as an accessible PDF, select File, Export… Type the file name and enter your destination. As the file format, choose Adobe PDF (Interactive). The program now allows you to enter additional export options. Under General, ensure that you select Create Tagged PDF, and Use Structure for Tab Order. Under Advanced, choose the Document Title as the Display Title, and choose the main language of the document. The selection of a main language is limited to a single language per document.
And last but not least, we recommend not to activate any security features. An accessible PDF should not be password protected.
Multilingual documents
Let's talk about multilingual documents. InDesign allows you to set the language of the content on the document and on the text level. When exporting the document to an interactive PDF, we have seen how to set the language on the document level.
Sometimes parts of your document may be in a different language, for example if you want to insert quotes using the original language. InDesign allows you to set the language of words using the Character palette.
Here we have a small example document with three paragraphs in three different languages. We can mark the language of each paragraph using the Language pop-up in the Character palette. These language settings are exported as part of the PDF. Unfortunately not as part of the tagging, so these settings will be ignored by screen readers.
We will explain how to repair this in Adobe Acrobat in another chapter, so that screen readers can make use of different languages.
Where to continue?
In this chapter you have learned how to create an accessible PDF document using Adobe InDesign. Depending on your personal interests you could continue with one of the following chapters:
- Microsoft Word
- Other authoring tools
- Testing PDFs
[Automated voice:] Accessibility. For more information visit: op.europa.eu/web/accessibility.