This document, EPUB Fixed Layout Accessibility, outlines the goals for EPUB accessible fixed layout ebooks while acknowledging the challenges unique to the FXL format.
+This document, EPUB Fixed Layout Accessibility, outlines the goals for EPUB accessible fixed layout ebooks while acknowledging the challenges unique to the fixed layout format.
EPUB fixed layout (FXL) publications, or publications where the print layout is preserved in the digital edition, have been around since before EPUB 3.0.1. These publications span a number of genres and types, from comic books, cook books, children's books, and more.
+EPUB fixed layout publications, or publications where the print layout is preserved in the digital edition, have been around since before EPUB 3.0.1. These publications span a number of genres and types, from comic books, cook books, children's books, and more.
-An accessible fixed layout EPUB file is one that meets the accessibility requirements of the Web Content Accessibility Guidelines 2 level AA [[wcag2]] and EPUB Accessibility 1.1 [[epub-a11y-11]], including color contrast, reading order, font layout, structural navigation, metadata, and text alternatives.
+An accessible fixed layout EPUB file is one that meets the accessibility requirements of the Web Content Accessibility Guidelines 2.x level AA [[wcag2]] and EPUB Accessibility 1.1 [[epub-a11y-11]], including color contrast, reading order, font layout, structural navigation, metadata, and text alternatives. Not all WCAG success criteria are applicable to EPUB documents, a more detailed list can be found in section 1.3.
-The main motivation behind creating fixed layout publications is the need to preserve the print layout of the book, either because of it's importance to the text (i.e. complex diagrams) or it's artistic purpose (i.e. illustrated text). However, these publications are often partially or completely inaccessible to people with print disabilities.
+The main motivation behind creating fixed layout publications is the need to preserve the print layout of the book, either because of the layout's importance to the text (i.e. complex diagrams) or it's artistic purpose (i.e. illustrated text). These publications can often be partially or completely inaccessible to people with disabilities, especially disabilities affecting vision or visual processing. However, the visual nature of fixed layout publications can also offer advantages for disabled readers. Graphic and visual design is about much more than making things look pretty, and well-designed publications can create reading experiences that aid in increasing understanding, information retention, conveying complex ideas, and more.
-This note serves to help EPUB creators, publishers, and reading systems address some of the common accessibility issues found in fixed layout content including navigation, reading order, and text alternatives. This document is a companion to EPUB Accessibility 1.1 [[epub-a11y-11]], specifically for fixed layout publications. All recommendations made in EPUB Accessibility 1.1 [[epub-a11y-11]], EPUB 3.3 [[epub-33]], and EPUB Reading Systems 3.3 [[epub-rs-33]] are applied and extended here.
+This note serves to help EPUB creators, publishers, and reading systems address some of the common accessibility issues found in fixed layout content including navigation, reading order, and text alternatives. This document is a companion to EPUB Accessibility 1.1 [[epub-a11y-11]], specifically for fixed layout publications. The recommendations made in EPUB Accessibility 1.1 [[epub-a11y-11]], EPUB 3.3 [[epub-33]], and EPUB Reading Systems 3.3 [[epub-rs-33]] are applied and extended here.
-In addition to the recommendations in this document, the Publishing Maintenance Working Group's Fixed Layout Accessibility Task Force is producing an accompanying techniques document to cover the technical side of FXL accessibility.
+In addition to the recommendations in this document, the Publishing Maintenance Working Group's Fixed Layout Accessibility Task Force is producing an accompanying techniques document to cover the technical side of fixed layout accessibility.
Fixed layout publications present some unique challenges for accessibility. The requirements laid out in EPUB Accessibility 1.1 [[epub-a11y-11]] recommend WCAG 2 level AA [[wcag2]], but for some use cases in fixed layout, that might not be possible without changes to the content. In this document, we will align recommendations with WCAG 2 level AA where possible, but will exclude success criteria that do not apply to fixed layout content.
+Fixed layout publications present some unique challenges for accessibility. The requirements laid out in EPUB Accessibility 1.1 [[epub-a11y-11]] recommend WCAG 2 level AA [[wcag2]], but for some use cases in fixed layout that might not be possible without changes to the content. In this document, we will align recommendations with WCAG 2 level AA where possible, but will exclude success criteria that do not apply to fixed layout content.
In particular, the needs of people with low vision or learning disabilities that rely on the transformation of text (i.e. dyslexia) are still almost impossible to accommodate in fixed layout content. EPUB creators concerned about this may choose not to use fixed layout.
@@ -89,25 +89,29 @@WCAG [[wcag]] is structured around four main principles: Perceivable, Operable, Understandable, and Robust. These principles are the foundation of web accessibility and a helpful way to group and understand the guidelines and success criteria required to make content accessible. Not all WCAG success criteria apply to fixed layout content.
+WCAG [[wcag]] is structured around four main principles: Perceivable, Operable, Understandable, and Robust. These principles are the foundation of web accessibility and a helpful way to group and understand the guidelines and success criteria required to make content accessible. Not all WCAG success criteria apply to fixed layout content, and fixed layout cannot meet all success criteria that apply.
We will use the principles to demonstrate how accessibility success criteria relate to fixed layout content.
Content must be presented and built in a way that allows it to be perceivable to all of a user's senses. This principle requires fixed layout content be built in a way that supports multiple reading methods - visual, audible, and tactile. This principle and its related success criteria are achieved by providing text alternatives for images, using proper markup to structure content, and ensuring visual content is well contrasted and designed.
+Content must be presented and built in a way that allows it to be perceivable to different senses. This principle requires fixed layout content be built in a way that supports multiple reading methods - visual, audible, and tactile. This principle and its related success criteria are achieved by providing text alternatives for images, using proper markup to structure content, and ensuring visual content is well contrasted and designed.
EPUB 3.3 [[epub-33]] supports multiple methods for content development, particularly for fixed layout content. The two primary methods are to use XHTML and SVG for building EPUB content documents. A third method used in many EPUB FXL books is to reference image files in the spine of the EPUB file. We will discuss the accessibility considerations for all three methods in this document.
+EPUB 3.3 [[epub-33]] supports multiple methods for content development, particularly for fixed layout content. The two primary methods are to use XHTML and SVG for building EPUB content documents. A third method used in many EPUB fixed layout books is to reference image files in the spine of the EPUB file. We will discuss the accessibility considerations for all three methods in this document.
+ +In addition to the core technologies mentioned in the EPUB 3.3 recommendation, EPUB accessibility may also require the use of the Accessible Rich Internet Applications [[wai-aria-1.2]] standard.
There may be cases when text appears on the page but is unnecessary, duplicated or otherwise confusing for it to be added to the reading order. e.g. page numbers, section or chapter headings which are already part of the publication’s structure or text used for visual effects.
+There may be cases when text appears on the page but is unnecessary, duplicated or otherwise confusing for it to be added to the reading order, e.g. page numbers, running headers and footers, or text used for visual effects.
+ +See the techniques document for guidance on how to apply this recommendation.
Fixed layout documents can be presented as synthetic spreads when a left and right page are presented together as a spread. As each page of the fixed-layout document is a separate XHTML document it is expected that reading order moves through there document from left to right (when using left to right page progression) but is not possible for the reading order to move from the left to the right and then back to the left page again.
+Fixed layout documents can be presented as synthetic spreads where two pages are arranged side-by-side. As each page of the fixed layout document is a separate XHTML document, it is expected that the reading order of the EPUB flows from one page to the next. Even if the content is presented in a synthetic spread, the reading order should not require that the reader move between pages to read the content in order.
If the text must be read in this way, the only solution to maintain the correct reading order is to convert the double page spread in to a single landscape page that contains the entire content of the spread and for the EPUB to be rendered as single pages.
The basic requirements for all images are to provide alternative text and extended descriptions when they contain information necessary to understanding the publication, which applies to fixed layouts. For example, while a reader may be able to follow the dialogue of a story when it is overlaid as text, only the placement on image might give context to what character is saying what.
-One challenge with fixed layouts is finding ways to describe the image and provide context given that there is no extra area on the page users can access in which to place a description. The other challenge is for content where the text is rasterized as part of the image, which can be unavoidable for content where the text is hand-drawn or part of the image.
+One challenge with fixed layouts is finding ways to describe the image and provide context given that there is no extra area on the page users can access in which to place a description. Another challenge is for content where the text is rasterized as part of the image, which can be unavoidable for content where the text is hand-drawn or part of the image. An additional challenge is fixed layout content where the pages or spreads are made up of multiple images that may require individual descriptions.
Image descriptions and alternative text do have limits in their ability to translate image content to text, those limitations include the ability to adequately map the flow of action on a page to text, or translation of visual effects to textual equivalents. Work continues in this area to improve this experience, and we will note gaps in the sections below.
+It is also important to mention decorative images, or images that provide no semantic value or meaning to the content. These images do not require alternative text, and in some cases, providing it may pose a challenge or frustration to the reader.
Describing images within a fixed layout book will somewhat depend on the type of book these images are within. For example describing a childrens picture book will be quite different than if this is a fixed layout graphic novel such as a comic book.
+Not all details are needed in writing alternative text for images, and what you do describe relies heavily on context. For example, if the image is described in the surrounding text, you only need to briefly describe it in the alternative text.
+ @@ -267,9 +278,7 @@If there are a group of images in sequence, you only have to describe details in the first image. In the proceeding images only mention what has changed.
-Not all details are needed in writing alternative text for images, and what you do describe relies heavily on context. For example, if the image is described in the surrounding text, you only need to briefly describe it in the alternative text.
- -Some fixed layout publications are constructed exclusively from image files in the spine. While this is not a recommended method in EPUB 3.3, some markets do use this format. Another method is to put image files into XHTML documents, but only the image file and no other content. Both of these methods fail to meet basic accessibility requirements, especially images in the spine.
+Aside from the ability to zoom, most fixed layout reading systems do not allow the reader to adjust the visual presentation of the content by resizing text or adjusting the text layout (letter, word, line spacing, or margins). EPUB creators also have the ability to set specific orientation settings for FXL EPUBs.
+Aside from the ability to zoom, most fixed layout reading systems do not allow the reader to adjust the visual presentation of the content by resizing text or adjusting the text layout (letter, word, line spacing, or margins). EPUB creators also have the ability to set specific orientation settings for fixed layout EPUBs.
-These limitations in how EPUB reading systems display FXL content mean that this content is exempt from some of these requirements, specifically, 1.3.4 and 1.4.10. These limitations also result in an automatic failure of 1.4.4 and 1.4.12. These constraints mean EUPB creators should consider these requirements as much as possible during the design of the content. EPUB creators can do this by considering:
+These limitations in how EPUB reading systems display fixed layout content mean that this content cannot meet some of these requirements, specifically, 1.3.4 Orientation and 1.4.10 Reflow. These limitations also result in an automatic failure of 1.4.4 Resize Text and 1.4.12 Text Spacing. These constraints mean EPUB creators should consider these requirements as much as possible during the design of the content. EPUB creators can do this by considering:
Success Criteria 1.3.1, 1.3.2, 2.4.6, and 3.2.4 all cover ensuring content is programmatically related and identifiable as it is presented visually. That visual presentation is essential for all kinds of content, but for fixed layout EPUBs, can be even more essential.
-Due to the constraints FXL presents, and the potential devices FXL content can be used on, EPUB creators need to consider how the visual design of their content may present challenges to users with low vision, cognitive, or learning disabilities.
+Due to the constraints fixed layout presents, and the potential devices fixed layout content can be used on, EPUB creators should consider how the visual design of their content may present challenges to users with low vision, cognitive, or learning disabilities. These recommendations are meant to be informative and are not required to achieve accessibilility conformance.
When designing this content, consider the following:
@@ -503,8 +518,6 @@Media overlays allow EPUB creators to create an enhanced textual reading experience by synchronizing text and pre-recorded audio content. Media overlays in EPUB (reflowable or fixed layout) are not equivalent to audiobooks. Media overlays are also not a replacement or substitute for features like screen reader support or text to speech. Currently, media overlays in EPUB only support synchronizing audio media with textual content.
-To maximize the effectiveness of synchronized text-audio playback for people with different reading needs, EPUB creators are strongly encouraged to meet the success criteria defined in WCAG [[wcag2]].
-The provision of synchronized text-audio playback helps address various user needs. It not only enables a seamless visual and auditory reading experience from beginning to end of an EPUB publication, but is useful to users who require audio playback (e.g., who cannot see the text or have difficulties reading visually) or who benefit from reading with text highlighting (e.g., readers with dyslexia).
Unlike purely linear listening experiences, EPUB with synchronized text-audio playback preserves the user's ability to navigate around the publication, such as via the table of contents, and also introduces audio-centric reading features like phrase navigation, and ways to control which parts of the content are read aloud.
@@ -581,7 +594,7 @@If the table needs to remain an image, another option is to use alternative text and caption or ARIA roles to describe the data in logical reading order. The caption could be used as a summary of the table, and the alternative text would dive deeper. You would start with describing what the header row is followed by what is presented in each row. You could then dive deeper and list all the data as it appears in reading order.
+If the table needs to remain an image, another option is to use alternative text, the figure or details elements, or adjacent text content to describe the table. A caption could be used as a summary of the table, and the alternative text or adjacent content would dive deeper. You would start with describing what the header row is followed by what is presented in each row. You could then dive deeper and list all the data as it appears in reading order.
Depending on the complexity of the image this may require complex description with one of the following formats:
@@ -602,9 +615,9 @@Provide an extended description for a table using either aria-describedby or aria-details.
The advantage of aria-details over aria-describedby is that it allows users access to the markup of the linked description (which could be the table markup if you put it, for example, inside a details element to collapse it). The current drawback, however, is that there isn't great support yet for the attribute. And expanding details element within a fixed layout page is also likely to wreak a bit of havoc when users click on it (unless you find a way to reliably position it offscreen, but then that limits who can access it).
The advantage of aria-details over aria-describedby is that it allows users access to the markup of the linked description (which could be the table markup if you put it, for example, inside a details element to collapse it). The current drawback, however, is that there isn't great support yet for the attribute. Expanding details elements within a fixed layout page is also likely to disrupt the page when users click on it (unless you find a way to reliably position it offscreen, but then that limits who can access it).
The aria-describedby attribute's big drawback is that it turns the description into one long text string that users have to listen to. There's no way to navigate the columns and rows or have headers read out, so it's likely going to be very difficult for users to make sense of except for very simple and very small tables.
+The aria-describedby attribute's big drawback is that it turns the description into one long text string that users have to listen to. There's no way to navigate the columns and rows or have headers read out, so it's likely going to be very difficult for users to make sense of except for very simple and very small tables.
Books with accessible elements require metadata to indicate how they are accessible, and if they present and hazards to the reader.
+Books with accessible elements require metadata to indicate how they are accessible, and if they present any hazards to the reader. A full description of accessibility metadata in EPUB can be found in section 2 of EPUB Accessibility 1.1 [[epub-a11y-11]] and the Schema.org Accessibility Properties for Discoverability Vocabulary.
-The schema.org property accessibilityFeature is used to define all accessibility features within the book.
The DAISY Knowledge Base also provides excellent guidance on the usage and definitions of Schema.org metadata in an EPUB file. In this section, we have provided some examples of what this metadata might look like depending on different fixed layout use cases.
-A few values that could apply to a fixed layout book might be:
+alternativeText - Images are described with alternative textlongDescriptions - Complex images are described in detailreadingOrder - Reading order of elements is the same between visual presentation and non-visualA common use for fixed layout is children's picture books, which feature expressive illustrations and small amounts of text. In this example, this is a book where the EPUB creator has done everything needed for accessibility.
-Certain accessibilityFeature properties, like displayTransformability should not be used with fixed layout content.
The schema.org property accessMode is used to define the ways in which this book can be consumed be that visual, textual, auditory, or tactile.
Cookbooks are commonly formatted using fixed layout, due to their highly visual layout. In this example, the publisher has created a cookbook that meets accessibility requirements, including providing a detailed table of contents and index.
-A picture book without live text would only have an accessMode of visual.
A fixed layout book which contains both text and images would have two separate accessModes defined.
The schema.org property accessModeSufficient is used to define the combinations in which this book can be consumed be that visual, textual, auditory, or tactile.
This example is for a children's book that uses media overlays. The audio for the book contains a potential sound hazard, so it is declared in accessibilityHazard and further detail is provided in the accessibilitySummary.
For picture books with no text, or no alternative text, the way one would consume this would be completely visually so having accessModeSufficient of visual would be solely defined.
For fixed layout books that have both visual and textual elements having accessModeSufficient of visual,textual would be appropriate. In addition, if the fixed layout book is primarily images that are fully described, textual would also apply, as this implies the boook is Screen Reader Friendly and can be fully read by assistive technology.
This example features a textbook that includes video content. The video content does not include audio descriptions, but as described in accessibilitySummary, the EPUB creator fully describes the video content in surrounding text. There are potential hazards due to the type of video content.
If a fixed layout book has all images fully described then having accessModeSufficient of textual would be appropriate which implies this book is Screen Reader Friendly and can be fully read by assistive technology.
As EPUB creators work on remediating their catalogues, some books may not be fully accessible or tested against WCAG requirements. It is helpful for readers to know the status of a book, even if it is not yet accessible, so they can make informed decisions when buying or borrowing.
+ ++<meta property="schema:accessMode">visual</meta> +<meta property="schema:accessModeSufficient">visual</meta> +<meta property="schema:accessibilityFeature">unknown</meta> +<meta property="schema:accessibilitySummary"> +This publication has not been accessibility tested, or had remediation work done. If there are any questions about this book's content, or an urgent need for an accessible edition of this book, please contact us at [help]@[publisher].com. +
The schema.org property accessibilitySummary is a human readable statement on how accessible or inaccessible the book is.
Manga is commonly distributed in fixed layout EPUB format, either with images as spine items or embedded in individual XHTML files for each page. Most manga features images where the text is part of the image and not provided separately.
-Fixed layout EPUBs are composed of a large variety of EPUB features, often using an extended set in comparison to reflowable EPUBs. To ensure accessibility in the reading system, this list of recommendations should be considered:
A reading system should provide information on accessibility metadata provided by the EPUB file in the OPF. Guidance for key information and proposed wordings are provided by the W3C Publishing Community Group Accessibility taskforce report: User Experience Guide for Displaying Accessibility Metadata 2.0.
+A reading system should provide information on accessibility metadata provided by the EPUB file in the OPF. Guidance for key information and proposed wordings are provided by the W3C Publishing Community Group Accessibility taskforce report: User Experience Guide for Displaying Accessibility Metadata.
While fixed layout formatting is often used to represent highly visual content, not all reading systems support visual display, and when visual display is available, screen sizes may be limited. Therefore, many reading systems might avoid supporting fixed layout content due to concerns about a poor reading experience. In addition to concerns about rendering, it must also be considered that many users face difficulties consuming and navigating complex fixed layout content. Alternative rendering methods should be considered as a replacement or addition to fixed layout rendering.
+Alternative rendering methods for ebook content are methods of rendering beyond the visual, specifically auditory and tactile rendering (i.e., screen reader output or braille). While fixed layout formatting is often used to represent highly visual content, not all reading systems support visual display, and when visual display is available, screen sizes may be limited. Therefore, many reading systems might avoid supporting fixed layout content due to concerns about a poor reading experience. In addition to concerns about rendering, it must also be considered that many users face difficulties consuming and navigating complex fixed layout content. Alternative rendering methods should be considered as a replacement or addition to fixed layout rendering.
If the fixed layout publication does not conform to the recommendations made in this document, or WCAG [[wcag2]], providing alternate renderings of the content may result in an unusable or poor reading experience. Content that is not formatted in conformance with WCAG may result in output that has an incorrect reading order, broken sentences, or choppy pronounciation. The user should be informed if the content does not have accessibility metadata that would provide clarity on whether alternate renderings are supported, such as dcterms:conformsTo with a value for WCAG, or metadata values that conform to properties like Supports nonvisual reading from the User Experience Guide for Displaying Accessibility Metadata.
There are ongoing discussions about transforming visual publications into reflowable textual content for complete AA compliance. While these are not in production yet, by creating our fixed layout with logical reading order, full image descriptions, and good semantics and structure where possible we are preparing our files in the best way for these future developments.
+ + +This document was a group effort, with many people generously contributing their time, expertise, and insight into its development. Special thanks must also be given to those that contributed sections of this document, including Gautier Chomel (EDRLab), Charles LaPierre (Benetech), and Susan Neuhaus (Neustudio).
+ +The following members of the Fixed Layout Accessibility Task Force also contributed to the development of this document:
+ +