Fixed Layout EPUB has the power to combine rich layouts built with illustrations, photography, graphic design and typography with animations, video, audio and interactions. It has the potential to make modern illustrated and non-fiction publishing that is visually appealing and/or helps communicate complex information. I spoke more about that here:
Many of the EPUB accessibility features found in reflowable EPUB can still be used in fixed layout. We can add accessibility to fixed layout EPUB in the following ways:
Reading order
Top of the list for the Diagram Center’s Top Tips for Creating Accessible EPUB 3 Files is that"All text must be available in a logical reading order”. When faced with a well designed but complex spread an experienced, the sighted reader will quickly make subconscious decisions on the hierarchy and reading order.
Unfortunately, the reading order of an InDesign page bears no relation to the position of the objects on the page or the styling used, but instead is presented in a reverse stacking order. It is not easy to understand the reading order or to influence it without affecting the design.
CircularFLO has reading order tools that help users visually define the reading order of their InDesign spreads and then applies that to the content on export. Sample output
Alternative text and extended image descriptions
Adding quality alt text to images is an important way to add the meaning of those image to those who may not be able to view them. Going even further and adding extended image descriptions can be useful to anyone who wishes to get more understanding about a key image. Rather than placing alt text into image metadata, the best place to add the most useful description is by adding it to the image once placed on the page, where the context of the image and the intended audience can be taken in to consideration.
InDesign has a rather disappointing manual and hidden away method to enter alt text and no way to add extended image descriptions.
CircularFLO has tools for large scale preparation, importing, sharing, spellchecking and exporting of alt tags and extended image descriptions. Video 1 & Video 2
Table of Contents
Many of the publishers of illustrated reference books that I work with do not use the InDesign generated Table of Contents. This leaves them with only visual table of contents on page.
Also, because fixed layout EPUB has a separate HTML page per book page, any longer book with a TOC spanning several book pages must therefore have an additional TOC for the ebook navigation.
CircularFLO users can add a Sections panel in order to enter title and page numbers to their InDesign files and generate a nested table on contents in the ebooks. Video
Section markers and landmarks
Because each page of a fixed layout EPUB is a separate HTML document, a page list can be easily generated(something which is something extra we can do for reflowable EPUB) but there is still a use for adding as section markers and landmarks to identify major sections of an EPUB. e.g. cover image, table of contents, and the start of the main body matter.
CircularFLO has tools to add a visual section marker / landmarks at a page level for reflowable and fixed layout. Video
Legibility & Readability
Because the reader is unable to influence the text presentation of the fixed layout EPUB in the same way as a reflowable EPUB(such as font style and size), general good practice for print graphic design and for web UX apply in fixed layout EPUB. Classic graphic design consideration such as grids, white space, complimentary font combinations, line length, leading and tracking and so on become more important. Here is a good article on the subject.
Text Contrast
Along with readability, the greater amount of design features of Fixed Layout EPUB might be expected to also have greater potential for text contrast challenges. Poor contrast between text and background colours can affect everyone but contrast is of greater importance for those with sight difficulties. A good resource is the WebAIM Contrast Checker.
CircularFLO and GreenLight have a tool that takes the colours from selected InDesign objects and checks and report on their contrast ratios. Video
Accessibility metadata
By declaring just how accessible(or not!) an EPUB3.2 file is, we can inform the retailer and reader about the features that the ebook has before purchase or download. InDesign does not have a way to add this metadata.
CircularFLO helps and GreenLight users can add A11y metadata to their InDesign files by using the CircularFLO Metadata Panel. Video
Media overlays
Adding pre-recorded audio that is synchronised with the words or images on the EPUB page can be more beneficial than synthetic text-to-speech for understanding and accessibility.
Fixed Layout(and also reflowable) EPUB3 can take advantage of these media overlays.
CircularFLO offers ways to add audio tracks and then automatically prepare InDesign files for read aloud media overlays. Video and sample file
Tables
I need help on this! Let’s start with a hand-coded example of an ideally made table in FXL?
Structural Hierarchy
“The use of heading tags ensures users do not have to rely on visual styling to understand and navigate the document outline.” - DAISY KB
As there is no inheritance between XHTML documents. How valuable is this when each page is separated anyway?
Reading order
Alternative text and extended image descriptions
Table of Contents
Section markers and landmarks
Legibility & Readability
Text Contrast
Accessibility metadata
Media overlays
Tables
Structural Hierarchy