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Adobe InDesign is one of the most widely used professional tools for creating ebooks, educational publications, technical manuals, reports, and other digital publications.

But exporting an InDesign document as an EPUB does not automatically make it accessible.

A visually polished ebook can still create serious barriers for readers who use screen readers, enlarge text, navigate with a keyboard, or depend on other assistive technologies.

Creating an accessible EPUB requires designers to think beyond the appearance of individual pages.

You need to consider semantic structure, reading order, headings, alternative text, navigation, tables, links, text resizing, language, and the way content reflows across different reading environments.

Recent versions of Adobe InDesign have also introduced accessibility improvements that make this process easier, including better text-resizing controls, AI-assisted alt text, accessible glossary support, and improved handling of context breaks.

Here is how to build a more accessible EPUB workflow in Adobe InDesign.

What Is an Accessible EPUB?

An accessible EPUB is an ebook designed so that readers with different abilities can access, understand, and navigate its content.

That includes readers who may:

• use a screen reader
• have low vision
• enlarge text substantially
• change fonts or spacing
• navigate without a mouse
• require strong color contrast
• have difficulty interpreting complex layouts
• rely on semantic document structure

The important word is structure.

A sighted reader can often understand a page by looking at its visual hierarchy.

A large headline clearly looks like a heading.

A photograph obviously belongs to the nearby article.

A sidebar looks separate from the main narrative.

A screen reader cannot rely solely on visual appearance.

The underlying EPUB needs to communicate those relationships structurally.

Why Reflowable EPUB Is Important for Accessibility

InDesign can produce different types of digital publications, but reflowable EPUB is particularly important for accessible publishing.

In a fixed-layout publication, the designer controls where everything appears.

That is useful for highly visual publications where maintaining exact page composition is essential.

But fixed positioning can also reduce flexibility.

A reflowable EPUB behaves differently.

The content adapts to the reader’s environment.

Readers may be able to change:

• font size
• font family
• line spacing
• margins
• screen orientation
• display size
• foreground and background colors

The content then reflows around those choices.

This adaptability can make reflowable EPUB much more suitable for accessible reading.

Accessibility Starts Before Export

One of the biggest mistakes designers make is waiting until the EPUB export stage before thinking about accessibility.

By then, many structural decisions have already been made.

A better approach is:

Plan → Structure → Design → Add Accessibility → Export → Validate → Test

Accessibility should influence the source InDesign document.

That means thinking about:

• paragraph styles
• heading hierarchy
• story order
• anchored images
• alt text
• tables
• links
• document language
• navigation

from the beginning.

Start with a Logical Document Structure

Before worrying about visual design, consider the logical structure of the publication.

For example, a book might contain:

Book title

Introduction

Chapter 1

Section 1.1

Section 1.2

Chapter 2

Section 2.1

Conclusion

Glossary

Index

That hierarchy should be reflected in your InDesign styles.

Don’t simply make text look like a heading.

Make it function structurally as a heading.

This distinction becomes extremely important when the content is converted into HTML-based EPUB structure.

Use Paragraph Styles Consistently

Paragraph styles are fundamental to a good EPUB workflow.

Instead of manually formatting headings, body copy, captions, and other content, create dedicated styles.

For example:

Book Title

Chapter Title

Heading 2

Heading 3

Body Text

Quote

Caption

List

Glossary Term

Glossary Definition

This gives the publication consistent structure and makes semantic export mapping much easier.

Styles should represent meaning, not merely appearance.

A paragraph isn’t Heading 2 because it happens to be 18-point bold text.

It is Heading 2 because it represents a second-level section in the document hierarchy.

Map Styles to Semantic HTML

EPUB is fundamentally based on web technologies.

Underneath the ebook interface, content is represented using technologies including HTML and CSS.

That means semantic HTML structure matters.

InDesign allows styles to be mapped to appropriate export tags.

A chapter heading might map to:

<h1>

A major subsection might map to:

<h2>

Body copy might map to:

<p>

The goal is to make the exported EPUB understandable structurally, not merely visually.

This helps screen readers and other assistive technologies navigate the publication.

Maintain a Logical Heading Hierarchy

Heading levels should follow a meaningful order.

For example:

H1 — Chapter

H2 — Main section

H3 — Subsection

Avoid choosing heading levels based solely on how you want them to look.

A common mistake is jumping from H1 directly to H4 because the designer prefers the appearance of the fourth heading style.

Appearance should be controlled through styling.

Semantic level should reflect document structure.

The two concepts should remain separate.

Reading Order Is Critical

A visually complex InDesign page may contain several separate text frames.

For example:

• headline
• introduction
• body copy
• sidebar
• photograph
• caption
• pull quote
• footer

A sighted reader can often determine the intended sequence instantly.

An EPUB reader or screen reader needs a logical content order.

If the underlying order is incorrect, the publication may become confusing.

The reader might encounter the caption before the image, a sidebar in the middle of a sentence, or a footer before the main body content.

Always think about the logical reading sequence independently of visual positioning.

Use Threaded Text Where Appropriate

Threaded text frames can help preserve a logical flow through long-form content.

For books, reports, articles, and manuals, maintaining the primary story as a coherent text flow can make EPUB export considerably more predictable.

This doesn’t mean every publication needs one enormous story.

But unnecessarily fragmenting content into dozens of unrelated text frames can make reflowable export more difficult to manage.

Design for the digital reading sequence as well as the printed page.

Anchor Images to Relevant Text

Images often need a logical relationship with surrounding content.

Suppose a photograph belongs directly after a particular paragraph.

Visually positioning the image near that paragraph doesn’t necessarily guarantee that the EPUB will preserve the relationship correctly.

Anchored objects can help establish where images belong within the content flow.

This becomes particularly useful when the EPUB reflows on different screen sizes.

The image can remain associated with the relevant section rather than depending entirely on fixed page coordinates.

Add Alt Text to Meaningful Images

Images that communicate information generally need alternative text.

For example:

Photograph of a restored nineteenth-century railway station with its original glass roof.

Alt text gives readers using screen readers access to information that would otherwise only be visual.

InDesign allows alt-text information to be associated with placed graphics for export.

Recent versions can also use AI to help generate descriptions.

Use AI-Generated Alt Text Carefully

Adobe’s AI-assisted alt-text capability can significantly accelerate the workflow.

InDesign can analyze an image and suggest a description.

That is particularly useful in image-heavy books and educational publications.

But the generated result should always be reviewed.

AI may recognize:

Person standing beside a building.

while the context requires:

Architect standing outside the newly restored Bauhaus building discussed in this chapter.

AI sees the pixels.

The designer, author, or editor understands the editorial purpose.

Use AI to create the first draft.

Use human judgment to create the final description.

Review Alt Text After Cropping Images

Recent InDesign improvements make this workflow more robust.

Suppose you generate alt text describing three people in a photograph.

Later, you crop the image so only one person remains.

The original description may no longer be accurate.

InDesign can indicate when existing alt text may need updating after certain image changes.

Don’t ignore these warnings.

Accessibility metadata should describe the final visible image, not an earlier version of it.

Mark Decorative Images Appropriately

Not every visual needs a description.

Consider:

• ornamental flourishes
• decorative background images
• non-informative separators
• purely aesthetic textures

If these images add no meaningful information, announcing them to screen-reader users may create unnecessary noise.

Decorative content should be identified appropriately so assistive technology can skip it.

A useful test is:

If the reader never knew this image existed, would they lose information?

If the answer is no, it may be decorative.

Charts Need Meaningful Alternatives

Charts require more careful treatment.

Imagine a line graph showing website traffic increasing from 100,000 monthly visitors in January to 250,000 in December.

Alt text saying:

Line chart showing website traffic.

is not enough.

The important information is the trend.

A more useful description could be:

Line chart showing monthly website traffic increasing from 100,000 visitors in January to 250,000 in December, with the strongest growth occurring during the final quarter.

Complex charts may require additional textual explanations or accessible data tables.

The goal isn’t merely to identify the visual.

It is to communicate its information.

Build Real Lists

If content is a list, use actual list formatting.

Don’t simulate lists using manually typed hyphens, spaces, or decorative characters.

Semantic list structure helps assistive technologies understand:

• where the list begins
• how many items it contains
• where each item begins and ends

This improves navigation and comprehension.

Again, the rule is:

Don’t fake structure visually when InDesign can represent it structurally.

Build Real Tables

The same principle applies to tables.

Don’t create a table by manually aligning text with tabs and spaces.

Use InDesign’s actual table functionality.

A proper table has meaningful relationships between:

• rows
• columns
• cells
• headers

Those relationships can then be represented more effectively in exported content.

Complex tables can still create accessibility challenges, so simplify them whenever practical.

Keep Tables as Simple as Possible

A visually sophisticated table may contain:

• merged cells
• multiple header levels
• nested structures
• decorative blank cells

That may look impressive on the page.

But it can be extremely difficult to navigate with assistive technology.

Ask whether the same information could be communicated through a simpler table.

Accessibility often rewards structural clarity.

Create Meaningful Links

Link text should describe its purpose.

Avoid:

Click here.

A screen-reader user may navigate through a list of links without hearing the surrounding sentence.

Several links all called “Click here” become meaningless.

Instead use descriptive language such as:

Download the Adobe InDesign accessibility guide.

or:

Visit the publisher’s accessibility resources.

The destination is now understandable from the link itself.

Avoid Raw URLs When Possible

Long web addresses can be unpleasant when read aloud by screen readers.

Instead of exposing a long URL in the visible content, use descriptive linked text where appropriate.

This improves both accessibility and visual design.

Define the Document Language

The EPUB should correctly identify the language of its content.

Screen readers use language information to determine pronunciation.

If a Dutch publication is incorrectly identified as English, the listening experience can become extremely poor.

Set the primary language correctly and pay attention to multilingual content where appropriate.

Language metadata may seem technical, but it directly affects usability.

Don’t Put Important Text Inside Images

A graphic may contain text as part of the image.

That can create problems.

Text inside an image may:

• not be available to screen readers
• not resize with the reader’s preferences
• become blurry when enlarged
• be difficult to search
• be difficult to translate

Whenever practical, keep important information as real text.

If an image necessarily contains meaningful text, ensure an accessible equivalent is available.

Design for Text Enlargement

One of the great advantages of reflowable EPUB is that readers can enlarge text.

Your publication should support that.

Don’t assume the reader will use the font size you selected in InDesign.

A person with low vision may increase the text dramatically.

The content should continue to work.

This is where recent InDesign improvements become particularly important.

InDesign 21.4 Improves EPUB Text Resizing

Adobe introduced additional controls for text resizing in reflowable EPUB with InDesign 21.4.

The objective is to reduce problems where text becomes clipped when readers enlarge it.

InDesign provides options affecting how CSS sizing rules are handled during EPUB export.

Depending on the content and export strategy, designers can allow frames and content to respond more appropriately to changes in text size.

This is an important accessibility improvement.

Why Fixed Dimensions Can Cause Problems

Imagine a sidebar designed to contain exactly 100 words.

At the original font size, it works perfectly.

A reader increases the text size to 200%.

If the sidebar retains rigid dimensions, the enlarged content may no longer fit.

Some text could become hidden.

A sighted designer reviewing only the default layout might never notice.

Accessible EPUB design therefore needs to anticipate user customization.

The reader—not the designer—ultimately controls many aspects of the reading experience.

Think in Relative Measurements

Responsive digital design often works better when measurements relate to the text rather than being rigidly fixed.

Relative units can allow:

• spacing
• indentation
• margins
• image sizing

to adapt more naturally when text changes.

Recent InDesign EPUB improvements increasingly support this responsive approach.

This requires a different mindset from print design.

Print asks:

Where exactly should this object appear?

Reflowable EPUB asks:

How should this object behave when the reading environment changes?

Avoid Over-Designing Reflowable EPUB

One of the hardest lessons for print designers is accepting that not every detail of a print layout should survive into a reflowable ebook.

Trying to force a complex magazine-style spread into a responsive EPUB can create poor results.

Instead, prioritize:

• content hierarchy
• readability
• semantic structure
• adaptable imagery
• logical navigation
• responsive text

The ebook doesn’t need to look identical on every device.

It needs to remain understandable and usable.

Create Accessible Context Breaks

Sometimes content changes context without introducing a new heading.

A novel might indicate a scene change.

An article might shift to another topic.

A traditional print design may use a decorative symbol or extra spacing.

Sighted readers understand the visual cue.

Screen-reader users also need that change communicated.

Recent InDesign versions provide improved support for accessible context breaks in EPUB workflows.

This allows structural meaning to accompany visual separation.

Make Glossaries Accessible

Glossaries are common in:

• textbooks
• technical manuals
• educational publications
• academic books
• professional reference materials

Visually, the relationship between a glossary term and its definition may be obvious.

Digitally, that relationship should also be represented semantically.

Recent InDesign improvements provide better support for accessible glossary export.

This is particularly useful for educational publishing where glossary navigation and comprehension matter.

Build Useful Navigation

A long ebook needs effective navigation.

Readers should be able to move efficiently between:

• chapters
• sections
• major headings
• reference material

A well-constructed table of contents is therefore important.

Navigation isn’t simply a convenience.

For people using assistive technologies, it can determine whether a large publication is practical to use.

Don’t Rely on Page Numbers Alone

Print publications revolve around page numbers.

Reflowable EPUBs don’t.

The number of screens or “pages” may change depending on:

• device
• font size
• orientation
• reader settings

Navigation should therefore rely on meaningful structure rather than fixed physical page references whenever possible.

This is another major conceptual difference between print and reflowable publishing.

Color Contrast Still Matters

EPUB readers may customize colors, but designers should still ensure that the default presentation provides adequate contrast.

Be particularly careful with:

• light gray text
• text over photographs
• colored text on colored backgrounds
• subtle interface-style elements

Readable contrast benefits everyone, particularly readers with low vision.

Don’t Use Color Alone

If a chart uses:

green = passed

and

red = failed

the meaning may be inaccessible to some readers.

Add another indicator:

Passed ✓

Failed ✕

or use patterns, labels, icons, or other redundant cues.

Color should reinforce information, not carry it alone.

Add Useful Metadata

EPUB accessibility also involves metadata.

A publication may need information describing:

• title
• author
• language
• accessibility characteristics
• navigation
• publication details

Metadata helps reading systems, libraries, retailers, and readers understand the publication.

Depending on your workflow, some metadata may require checking or refinement after export.

Export Is Not the End

This is perhaps the most important lesson.

When InDesign finishes exporting the EPUB, the accessibility work isn’t finished.

The EPUB needs to be tested.

Think of export as the beginning of quality assurance.

Validate the EPUB

Use appropriate EPUB validation and accessibility-checking tools.

These can identify technical problems such as:

• invalid markup
• structural errors
• missing metadata
• accessibility issues
• broken references

Automated tools are valuable because they can detect problems across large publications quickly.

But they cannot evaluate everything.

Test in Multiple Reading Systems

An EPUB may behave differently across different readers.

Test important publications in multiple environments where practical.

Check:

• navigation
• images
• headings
• text resizing
• links
• tables
• lists
• context breaks

Don’t assume that because the EPUB works in one application, it works everywhere.

Test with a Screen Reader

One of the best ways to understand your EPUB is to listen to it.

Use a screen reader and navigate through the publication.

Ask:

• Can I move between headings?
• Does the reading order make sense?
• Are images described meaningfully?
• Are decorative images skipped?
• Do links make sense out of context?
• Can I navigate the table of contents?
• Are tables understandable?
• Does the content remain logical when I cannot see the layout?

This can reveal problems that are almost invisible during visual inspection.

Test Extreme Text Enlargement

Don’t test only the default text size.

Increase the font size substantially.

Then check:

• Does content disappear?
• Do images interfere with text?
• Does navigation remain usable?
• Do callouts still make sense?
• Does anything become clipped?

Accessible design needs to survive user customization.

Use EPUBCheck

EPUBCheck is widely used to validate the technical conformance of EPUB publications.

It can identify structural and packaging problems that may prevent the ebook from behaving correctly.

Technical validity isn’t identical to accessibility, but it is an important foundation.

An inaccessible EPUB can be technically valid.

An invalid EPUB creates additional problems.

You generally need both technical and accessibility testing.

Consider Ace by DAISY

Ace by DAISY is a valuable tool for automated EPUB accessibility evaluation.

It can analyze EPUB content and identify potential accessibility problems that require attention.

Automated testing cannot replace human evaluation, but it can dramatically improve quality assurance.

A strong workflow combines:

EPUB validation + automated accessibility testing + manual review

Keep the Source Document Clean

Accessible EPUB production becomes easier when the original InDesign document is well organized.

Avoid unnecessary complexity.

Use:

• consistent styles
• logical stories
• real lists
• real tables
• anchored images
• meaningful object descriptions
• structured headings

A clean source document produces a much better starting point for export.

Build an Accessible EPUB Template

If you regularly create ebooks, build accessibility into your InDesign template.

Define:

• heading styles
• body styles
• list styles
• caption styles
• glossary styles
• table styles
• semantic export mappings
• image handling conventions
• navigation structure

Then every new project begins with a better foundation.

Accessibility becomes part of the system rather than a last-minute repair job.

An Accessible EPUB Checklist

Before final delivery, ask:

• Is the document language correct?
• Is the heading hierarchy logical?
• Are paragraph styles used consistently?
• Is the reading order meaningful?
• Are important images anchored appropriately?
• Do meaningful images have useful alt text?
• Are decorative images handled correctly?
• Are lists real lists?
• Are tables structurally valid?
• Are links descriptive?
• Can text resize without being clipped?
• Is color contrast adequate?
• Is meaning communicated without relying only on color?
• Is navigation complete?
• Is accessibility metadata present?
• Has the EPUB passed technical validation?
• Has it been checked with accessibility tools?
• Has it been tested manually?

If several answers are “no,” the publication probably isn’t ready.

The Role of AI in Accessible EPUB Production

AI is becoming increasingly useful in this workflow.

Today, one of the clearest examples is generating image descriptions.

In the future, AI could potentially help identify:

• missing alt text
• poor heading structures
• unclear links
• suspicious reading order
• inaccessible tables
• text-resizing risks
• missing semantic relationships

But AI should remain an assistant.

Accessibility is ultimately about whether another human being can use the publication successfully.

That requires human evaluation.

Accessible EPUB Is Better Publishing

It’s easy to think about accessibility entirely in terms of regulations and compliance.

But accessible EPUB practices often improve the publication for everyone.

Clear headings improve navigation.

Good contrast improves readability.

Responsive text improves reading on small devices.

Meaningful links improve usability.

Simple tables improve comprehension.

Logical structure makes content easier to maintain.

Accessibility often aligns with good information design.

Final Thoughts

Creating an accessible EPUB with Adobe InDesign requires a different mindset from traditional fixed-page design.

In print, the designer controls the page.

In a reflowable EPUB, the reader controls much more of the experience.

They may change the font.

They may double the text size.

They may listen instead of look.

They may navigate through headings rather than pages.

They may never experience the carefully composed spread you see on your monitor.

That isn’t a failure of design.

It is the nature of accessible digital publishing.

The designer’s job shifts from controlling every coordinate to creating a robust content structure that adapts to the reader.

Adobe is making that easier with AI-generated alt text, improved text resizing, accessible glossary support, context breaks, and other EPUB enhancements.

But the foundation remains the same:

Structure your content logically.

Use semantic styles.

Describe meaningful images.

Design for reflow.

Create useful navigation.

Validate the export.

Test the actual reading experience.

Do those things consistently, and InDesign becomes much more than a tool for exporting ebooks.

It becomes a powerful platform for creating digital publications that more people can genuinely read and use.