Ask the Expert: EPUB fixed layout

In this session host Katie Durand and accessibility expert Gregorio Pellegrino from Fondazione LIA dive into the opportunities and challenges in making accessible Fixed Layout EPUBs. 

The expert

Gregorio Pellegrino, Chief Accessibility Officer at Fondazione LIA, is an Italian software engineer with a strong focus on improving digital accessibility for visually impaired individuals. His expertise is reflected in his co-editing of key industry documents, such as W3C EPUB Accessibility 1.1, the Accessibility Metadata Display Guide for Digital Publications 2.0, and the EPUB Accessibility - EU Accessibility Act Mapping. He is also technical leader of the DAISY Consortium's "Accessible EPUB from InDesign Expert Group," working with Adobe to enhance the accessibility of EPUBs exported from InDesign. Pellegrino's work with organizations like W3C, DAISY, and EDItEUR helps shape global accessibility standards. Through his consulting, training, and standards development efforts, he continues to support more inclusive reading experiences in digital publishing.  

Questions and answers

What is the definition of a fixed EPUB?

When we speak about fixed layout publications we mean publications where the layout in the digital format is preserved as it is in the print edition. That means that each element on the page has an absolute position. So it has a X and Y position in the element. This is in opposition to reflowable publications. Fixed layout publications are all kinds of formats where the content does not adapt to the different screens where it is visualized, while reflowable content automatically adapts to the different screens. Pdf is an example of a fixed layout format and you experience this when you try to read an A4 size page on you smartphone; you have to literally move the page on our screen to being able to read it. 

On the opposite side there are modern websites that are developed using reflowable options and are responsive; the content automatically adapts to the dimensions of our screen. So if we speak about fixed layout in EPUBs, we mean which are displayed in a way that is fixed for the end user and is the same on every device where it's shown.  

How does a fixed layout EPUB differ from a Pdf?

1. For the technical architecture of an EPUB, we use web based technologies: HTML, Css., Svg. While in Pdfs we use a technology that is called postscript, that was developed in the nineties by acrobat that was developed for having in the digital world the printer replica of printed documents. Pdfs can be made accessible. And in particular there is a standard that is called Pdf ua. The latest version is 2, which stands for universal, accessible.  

2. In EPUB, with the use of HTML, we can manage semantics very well. We can provide a great screenreader support, and we can use another technologies. That is part of the EPUB world. That is the media overlay technology. The media overlay technology is a technology where the content Creator can sync audio like narrated audio with the text so that the end user can read the content while listening to it. It's not required for making accessible EPUBs to use the the media overlay technology, but for sure is a technology that can enable accessibility. And this is not available in in Pdfs. 

3. Pdfs are not that well accepted by the distribution channels. Big retailers, big distribution platforms do not accept Pdfs as a format for distributing ebooks. That's why EPUB fix layout was born to allow a similar experience of Pdfs. 

4. On the reading experience side, the 2 formats are quite similar for an end user. For sure, the reading apps differ.  

What are the accessibility criteria or standards that relate to fixed layout EPUBs?

When you create fixed layout publications in EPUB you have to declare that in the metadata. By declaring this in the metadata, if your publication is fixed it means that the reading system will use another set of technology for displaying it. 

Another important thing from a standard point of view is that fixed layout publications in EPUBs may be made using 3 different technologies. So the content itself in a fixed layout publication can be in HTML, XHTML, used for websites and most of the reflowable publications, or it can be made using SVG which is an open standard for making vectorial images. SVG can be made accessible and is an open standard of the web. The 3rd way for making fixed layout that is not mentioned in the standard, but we know is widely used, is using rostering images for pages. These are Jpeg or png images; plain images like a scan or photograph, or screenshots of the printed page. This 3rd solution is not standardized, but is widely used, mostly for comics, books, and mangas.  

Does EPUB accessibility 1.1 cover fixed layout EPUBs as well as reflowable EPUBs?

Some rules can be applied to fixed layout EPUBs as well. There are some requirements about accessibility metadata and this is a requirement that can be fulfilled by fixed layout EPUBs as well. There are requirements on following the web content, accessibility guidelines. There are some requirements about media overlay, if present. So the synchronized audio and text that can be fulfilled by fixed layout, and there are some requirements about page list and page navigation that is simpler to be fulfilled in fixed layout than air flow. However, creating a fixed layout EPUB that follows all the requirements of both EPUB Accessibility and web content accessibility guidelines is challenging.  

Is the fixed layout still the best format for publishers of for example educational books or children’s books?

In some cases, using a fixed layout is a fast way to create an e-book. You can just use the same design as the printed version. This is often easier than making a reflowable version. 

In the educational market, fixed layout is still used a lot. Many users like it when the digital version looks like the printed one. But we also see more and more publishers offering a reflowable version as well, so readers can choose. Often, the books are read on a platform managed by the publisher, and that platform shows both versions: fixed and reflowable. 

What we see in practice is that almost everything published as fixed layout can also be made reflowable. Yes, you lose the exact visual layout, like where things are placed on the page, but you can still give the same meaning and content to the reader. That’s why we think you shouldn’t only offer a fixed layout for educational books. It’s better to offer both, and let the reader choose what works best for them. 

For children’s books, it’s a bit different. These books are usually very visual, with a lot of pictures and only a little text. Making a reflowable version is possible, but not easy. And in the end, the reflowable version will still look a lot like a fixed layout, big images and very little text. So in that case, fixed layout makes more sense. 

One important note about accessibility: the European Accessibility Act says that children’s books, art books, and comic books should be made as accessible as possible, within the limits of what is technically and practically possible. Right now, making fully accessible fixed layout books is still difficult. That’s a limitation we need to be aware of. 

There are also other types of books that are often published in fixed layout, like cookbooks or influencer books. These need to look exactly like the printed version. But even then, most of these books could also be made as reflowable. 

One last thing: fixed layout is not always easy for readers to use. You need a big screen to read it properly. So think about your readers. Are they using smartphones or small e-readers? Then a reflowable version is probably better. It might take more effort to make, but we’ve seen a lot of creative solutions. You can do a lot with reflowable formats, even with some design limits. 

If fixed layout is chosen as the best option for a children’s book, how can these books be made accessible?

It is possible. At Fondazione LIA, we conducted a research and development project two years ago for an Italian publisher, Edizioni Sonda. The book in question was about disabilities, aimed at children, and featured a rich, colorful layout full of illustrations.  

There are several challenges: 

1. Color contrast: The original print version had poor contrast, so we had to propose changes that complied with the Web Content Accessibility Guidelines (WCAG). Because the book was translated from another language, changes needed approval from the original publisher and author. So: if you're creating a fixed layout, start with accessible color contrasts from the beginning. 

2. Semantics: We used Adobe InDesign as the authoring tool, which does not support proper semantic tagging (like headings and lists). We had to manually correct the code to fix this. 

3. Reading order: InDesign also doesn’t allow clear definition of reading order, so we managed this manually too. 

We succeeded in making the fixed layout accessible, but it required a lot of manual work. This is largely because current authoring tools don’t yet support accessibility for fixed layouts very well. 

Another aspect was alternative text. Many images in the book were decorative, so we simply marked them as such. For the meaningful ones, we added proper alt text. 

Do reading systems and screen readers recognize the semantic information added to fixed layout EPUBs?

Yes, they do, if the EPUB is well-structured. Fixed layout EPUBs are typically made using either HTML or SVG. We focused on the HTML approach because it allows rich semantic tagging. 

Most reading systems use "web views", essentially browsers without a user interface. On iOS, that’s Safari; on Android, it’s Chrome. So, the EPUB is rendered like a webpage, and both platforms support screen readers (VoiceOver on iOS and TalkBack on Android). 

This means if the EPUB is semantically rich and uses proper ARIA roles, the assistive technologies will recognize and read all relevant content: headings, lists, alt text, etc. In other words, screen readers can handle accessible fixed layouts quite well. 

What are the main disadvantages of fixed layout EPUBs in terms of accessibility? And how do you decide between reflowable and fixed layout?

The biggest drawback is that fixed layouts don’t provide a good reading experience for people with low vision. It’s hard to adjust text formatting (font size, line spacing, etc.), which is essential for many readers. While there are some workarounds using JavaScript to allow formatting changes, these aren’t standardized. 

Another disadvantage is the lack of proper authoring tools. Making a fixed layout accessible requires a lot of manual work, which makes the process expensive. 

So, if both formats are an option, I would always recommend choosing reflowable. It’s better for accessibility, for mobile reading, and for a wider audience. Reading a fixed layout on an e-reader, for instance, is frustrating—zooming and slow refresh rates make it nearly unusable. 

That said, if the layout is essential to the content, like in many children’s books or art books, a well-made accessible fixed layout can still be the right choice. Just be aware that the standards for fixed layout accessibility are still evolving, so you're working in a space that’s very much under development. 

What about scientific publications with complex visuals like graphs and charts? Can they be made reflowable?

In our experience, yes. We haven't yet encountered scientific publications that couldn’t be made reflowable. The main challenge tends to be complex tables, especially large ones, which are hard to display well across devices. But that’s an issue for both fixed and reflowable formats.  

Are there any limitations in reading systems that affect accessibility of fixed layout EPUBs?

Not really. As long as a reader supports fixed layout EPUBs, accessibility works fine, thanks to the fact that most use browser technology under the hood. 

Is it possible to make an accessible fixed layout EPUB using hidden text behind full-page images (like screenshots)?

Technically, yes. But this isn’t considered “born accessible.” You must perfectly align the hidden text with the image for low vision users who rely on both visual and audio cues. Misalignment can cause confusion. It’s possible, but time-consuming and not the preferred method. Creating accessible HTML from the start is usually the better approach.