This list is intended to serve as a starting point for your EPUB Quality Assurance process. Each section contains information about common best practices and suggestions for creating high-quality EPUB files. If you would like to suggest that something be added to this list, please contact us!
- It is recommended that you test your EPUB file on devices for all of the retailers you will be targeting. Please see the FlightDeck Handbook for instructions on how to load your EPUB files on most of the major eBook devices.
- Scroll/page through the entire eBook on at least one device, looking for:
- Content that is in the wrong location. This is common for images, sidebars, and other elements that have to be moved in the conversion process.
- Content that is missing.
- Page breaks before major sections (parts, chapters, etc.).
- Other major or consistent formatting issues that catch your eye.
- The EPUB Metadata should include, at minimum, the title, author, language, and ISBN.
- Other common information includes: publisher, publication date, other creators/contributors, subjects/keywords, description, and rights. This information can all be edited in FlightDeck’s Metadata Editor.
- Ensure that the title in the metadata matches the official title of the book as seen on the title page and front cover.
- Website addresses should be linked and should point to active sites when available. Links to known broken locations should not be linked and should be noted in the text as broken. See your EPUB's Stats page for an easy-to-use list of the external links in your EPUB file.
- References to “chapter 1”, “page 123”, “figure 1.2”, etc. should all be linked to the proper location in the eBook.
- Some publishers link chapter names to the TOC. If this is done, ensure that each link points to the correct location in the TOC, not just the top.
- Most retailers recommend that embedded fonts not be used for the main body text, only for special sections, headers, etc.
- If your eBook contains embedded fonts, your QA process should also include testing to ensure that the font-formatted content displays acceptably when the embedded fonts are turned off. This is usually done in the reading system’s user settings.
- Embedded fonts should be optimized for use on screens. Test their display at both small and large font sizes. Ensure that the glyphs are clear and readable on both E Ink and LCD displays.
- Front cover should include both the title and the author.
- Remove any print-specific information (print design awards, etc.).
- Ensure that the title matches the official title of the book as seen on the title page and in the metadata.
- Include the eBook ISBN(s). Some publishers remove the print ISBN, but if it is included, it is best to note what the ISBN relates to. For example: “978-1-23456-789-0 (trade paperback)”
- Remove print-specific information such as the printer’s key, paper the book was printed on, and font references that do not apply.
- The Cataloging-in-Publication data does not apply to eBook files. In most cases, these sections should be removed. If they are maintained, they should be marked clearly as relating to the print edition.
Table of Contents
- Some publishers like to move the Copyright, Other Books, and similar content to the back of the eBook. This is usually done to allow the automatic 10% samples created by retailers to include more regular reading content. If this is done, be sure to change the Table of Contents ordering to show the actual order of the book content.
- Check the linking of each item in the TOC to ensure it points to the correct location.
- Ensure that the structure of the TOC elements is correct, both in the HTML and in the navigation (NCX) view.
- When appropriate, include the PageList, List of Figures, List of Tables, etc.
- Include the <guide> in EPUB 2 and the landmarks in EPUB 3.
Special Characters and Unicode
- All special characters, including non-Latin text, wingdings, and other non-standard textual content, should be tested for support in the target reading systems. This is especially true when dealing with characters that require specialized fonts for proper display.
- Ensure that all special characters and foreign language text displays in the default system fonts. This can usually be checked by turning off “Publisher Defaults” or changing the default font in the reading system settings.
- Ensure that Unicode content is used throughout the book. Non-Unicode fonts will sometimes cause Latin characters to display as a character in a non-Latin language (for example, “a” displaying as “א”). These fonts need to be removed, and the text in question needs to be replaced with Unicode text.
- Ensure that all right-to-left, top-to-bottom, etc. text displays properly (is not backwards, etc.) and degrades gracefully if possible.
- If your Unicode content includes characters from the Private Use Area, ensure that you have an embedded font with the proper support, and consider including a warning to users about the need for embedded font support when reading the eBook.
- If your EPUB has a print counterpart, it is best to include the page numbers in the code in the proper location. Please see the Handbook for more information.
- If the EPUB does not have a print counterpart, adding page numbers may still be helpful for other features (like linking an index). The page numbers in this case can be added where you see fit.
- If you include page numbers in your EPUB, be sure to add a PageList to your NCX (EPUB 2) or HTML Nav doc (EPUB 3).
- Ensure that all Part and Chapter headings are properly sized and aligned.
- Watch for line-height (leading) on long headings, ensure that the text wraps correctly and is not bunched up.
- Remove hyphens from headings whenever possible. This can be done in the CSS with:
-epub-hyphens: none !important;
hyphens: none !important;
- Ensure that headings within the chapters are designed for consistency and structural clarity. The structure of the content should be understandable based on the size and style of headings.
- Formatting in an eBook file will inevitably be different from a print counterpart. It is important to ensure that the styling is both consistent throughout the book and consistent with the overall look and feel of the print counterpart.
- Text colors may be used, but they should not be too light. Light text color may be unreadable on grayscale E Ink screens.
- Bold, italic, small caps, and other character styles should be checked. If you are concerned about accessibility or semantic markup, be sure to use the correct HTML and CSS code for those elements based on the context. Also, note that small caps have varying levels of support on different reading systems, with systems that use the Adobe RMSDK (like the NOOK) not supporting the standard
- Format poetry with proper hanging indents and stanza breaks.
Worksheets, Quizzes, etc.
- Content that is intended to be filled out in a print book may not be appropriate for eBooks. In many cases, we recommend removing these and hosting them as PDF files on your website where readers can print them out at home. In some cases, you may also want to consider converting them into a web-based form or tool.
- While EPUB 3 promises to allow more interactivity with this kind of content inside the eBook file, that capability is not currently supported in the major eBook devices.
- If you do include this content in your eBook file, be careful to ensure that the formatting works well on different device screen sizes and at different font sizes.
- It might be necessary to include an image of the form to give readers a more understandable view of the content. Be sure to include accessible descriptions for readers with vision impairments.
- All notes in the eBook should be linked both directions.
- In reflowable eBook files, footnotes (bottom of the page) are usually converted to endnotes (end of the chapter or book). If footnotes are going to be kept within the content, it is best to place them after the paragraph or section, not in between words or sentences.
- Notes that reference other notes should include links.
- Depending on the formatting of the endnotes (e.g., if each is displayed on its own page or as a pop-up), you may want to replace “ibid.”, “loc.cit.”, and “op.cit.” with full references to ease possible reader confusion and frustration.
- While some publishers prefer to remove indexes from their eBook files, that is not the best practice.
- Indexes should be complete, with all items and reference numbers included.
- Reference numbers (usually page numbers) should link to the proper location in the book. This can be either the print page number anchor or an anchor specific to that reference.
- Cross references (“see” and “see also”) should be linked to the proper index reference.
- It is recommended that a long index be given its own structural contents list (A, B, C,etc.) to allow easier navigation.
- References to figures, images, and tables should link directly to the element, not just to the page on which it appears.
Other Back Matter
- About the Author should include up-to-date information.
- Links to the author/publisher website should be active.
- Bibliography should be formatted properly. If long website links are included, it is best to left-justify the text of the whole bibliography to avoid large spacing gaps.
- Back covers are not normally included in eBooks.
- If included, remove the barcode, print ISBN, and price.
- About the Author information is usually best included as real text in the eBook.
- Check all images for quality and readability on target reading systems.
- Images should ideally be 300ppi or a similar resolution.
- Images that are intended to be viewed full-screen should be a minimum of 1000px on the long side.
- Be careful about not making the dimensions too large. See the Retailer Acceptance Grid for details on individual retailer specs.
- All images should be scaled with CSS when needed. Do not scale the image itself to make it fit into a specific location or space, as this can cause images to become too small to be viewed well.
- Note that most reading systems allow the reader to double-tap/double-click on the image to view it in a larger viewing area. This feature should be used to test each image’s size and ensure that large images are able to be zoomed for closer inspection when needed.
- Images should be saved in an RGB color space, not CMYK.
- Images should not be larger than 10MB each. This allows reading systems to more easily load the images into memory when needed.
- It is recommended that images have transparent backgrounds whenever possible and appropriate. This assists with proper display in the “night time” and “sepia” reading modes found in many reading systems.
- Captions should be properly aligned and should appear on the same page as the image whenever possible. This can be done by scaling the image with CSS to leave space for the caption beneath.
Tables and Charts
- Content that is not actually tabular in nature (for example comparative lists) should not be formatted as a table just to match the print book design. This also includes tables that involve lots of content in each cell, or that are only two columns, with the left column used for headings. These kinds of tables should all be converted into regular paragraph text.
- Tabular content should be coded in HTML. Tables should not be inserted as images unless absolutely necessary. If this is done for any reason, we recommend including the appropriate accessibility descriptions, as well as fallbacks to HTML tables, wherever possible.
- Note that some reading systems allow the reader to double-tap/double-click on the table to open it in an expanded window for easier viewing. All tables should be tested in this window for proper formatting.
- Be cautious when testing tables on small screens. Ensure that they are readable and that the content fits well on the screen when possible.
- Charts that use color in meaningful ways should include explanations where needed for readers with grayscale screens.
- Charts and graphs with text should be readable on screens of all sizes.
- In some cases, it may be helpful to place very large tables on your website and link to that location so that the reader can access the content without the screen size and viewing restrictions of their reading device.
Audio and Video Content
- If you are embedding audio or video content in EPUB 2 files, realize that only certain vendors will support those files. For future compatibility, EPUB 3 is recommended. See the Retailer Acceptance Grid for your title for more information.
- Include proper fallbacks for your media content. This may include a flat image or an explanation that the media content is not supported in the reading system they are using.
- Whenever possible, it is best to include a link showing where the reader can access the media content online.
- Audio and video files should be encoded according to the specs supported on the target reading systems and retailers. These specs are not always the same, so be careful what you provide. See the Retailer Acceptance Grid for more information
- Videos should always include a poster image.
- Be careful about file size. Retailers have size limitations and recommendations that help manage user expectations and experiences. It is usually recommended that media-enhanced EPUB files not be larger than 500MB.
- Interactive content is supported in some reading systems. Be sure to test your eBook file in ALL of the reading systems you are targeting.
- Watch out for conflicts with built-in reading system functionality, like page turn mechanics.
- Whenever possible, provide fallbacks to interactive elements. This protects against unusable eBooks in future reading systems or when updates to current systems break your functionality.
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