This chapter shows how to create accessible EPUBs with Adobe InDesign.
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Adobe InDesign can be used to create documents, including EPUBs.
Accessible images require alternative texts, which can be stored in the metadata as part of the image, so it can be reused in other documents. We will use Adobe Bridge, which opens a file browser to select the file. Bridge indicates editable metadata attribute fields with a little pen. In the IPTC Core attributes we can edit the description.
Pros of having the alt text in the metadata: it becomes part of the file; it can be reused in multiple documents; all text descriptions in the metadata can be used to search for an image; when the alt text in the image is updated, it is automatically applied to all relevant documents. The con or limitation is that metadata are limited to a single language.
We open a document in InDesign. It contains headings, links, images, a list, a table and a complementary block of information about the author.
To bring structure using the headings: Window, Styles, Paragraph Styles. All text is associated with a style. We create a new style named Heading Level 1. To be exported as a level 1 heading, we define this using the Export Tagging options. Under EPUB and HTML, Tag, we assign the H1 tag for a level 1 heading. Each heading is marked with its own style, named in a way that we can identify its level. You can use multiple styles for the same heading level.
For an existing document, to edit all export tags at once, go to the Paragraph Styles panel and select Edit All Export Tags. Activate the EPUB and HTML options. If you want to modify a tag assignment, use the pop-up to select the appropriate tag value.
Select the text you want to convert to a list and select Type, Bulleted and Numbered Lists, Apply Bullets. Bulleted lists cannot be nested in InDesign.
You can also create and modify tables. The first row is its header. There are 2 options for defining table headers. First: select Table, Convert Rows, To Header. Second: select Table, Table Options, Headers and Footers.
To create a table of contents, select Layout. In the modal dialogue, name it and select a style to define its appearance. Add the heading styles to be used for creating the correct order. The lines in the table of contents do not use the same styles as the originating headings. We can define the hierarchy of our table of contents selecting the different heading levels in the correct order.
To save the settings for this table of contents as a style, click the Save Style button and give the style a name. We position the frame of the table of contents inside the visible area of the page, but it doesn’t need to be visible. If it is outside the visible area, a user would be able to access it by the navigation functions.
To create a hyperlink, select the text, right-click and select Hyperlinks, New Hyperlink. Enter the web address. Under the Accessibility tab, you can add alt text. Click OK. Once the e-book is exported, this link will be clickable for the user.
To add an alt text to an image, right-click, select Object Export Options and Alt Text tab. From the Alt Text Source pop-up, select which metadata attribute to use as alt text. If you do not want to use the metadata, select Custom and type it.
If your object uses a graphic format that is compatible with EPUB (PNG or JPEG), then you do not need to change the appearance of the layout. If your object is not compatible, it needs to be rasterised to be compatible with EPUB.
To anchor the image in the text, use the anchor icon on the image frame. Click and drag the anchor to the target position in the text, and release the mouse button. When the document is exported to EPUB, the image will be positioned after that paragraph, so it cannot be in a different page. To see the position of the anchors, select View, Extras, Show Text Threads. The dashed line indicates the connection between the image and its position in the text.
To define a reading sequence, open the Articles pane, select Window, Articles. Drag and drop the individual frames into the Articles pane in the sequence in which they should be read out.
Check that the language of your default styles matches your primary language. InDesign allows to set the language using the Character settings. Select Window, Type & Tables, Character. Select the text for which you want to define the language. Select the language from the menu.
To save your file as an accessible e-book, select File, Export, type the file name and enter your destination. As the file format, choose EPUB (Reflowable). Under General, select EPUB version 2 or 3.
For the sidebar navigation, we want a multilevel table of contents. We choose the style for the table of contents, so all our previously defined settings are applied.
If you are creating an e-book for distribution, you should add metadata to your product. Finally, you can configure which program to use to view your EPUB once generated.