EPUB vs. PDF – Digital book formats

Readers enthralled by eBooks are showing up more and more on airplanes, buses, subways, doctors’ waiting rooms, and anywhere else people are likely to read. The increasing array of eBook readers has drawn more attention to the EPUB format. So what is this format? How do you design for it? How do you create it? And how does it compare to PDF?

What is EPUB?

Introduced in 2007, EPUB became the official standard of the International Digital Publishing Forum (IDPF). It enables text to reflow for different eBook readers and orientations, therefore it’s most useful for electronic publications that are mostly text. Unlike PDF (Table 1), EPUB documents have no “pages” per se (because the pages are made by the eBook reader). This makes the flexible-layout EPUB format difficult to use for complex page layouts with multiple, grouped photos and sidebars. The real selling point of EPUB is that the flexible format keeps text the same size and thus facilitates reading of text-heavy documents (Figures 1, 2). (Think about this the next time you are on a bumpy bus, train, or airplane.) At the same time, the newer, fixed-layout EPUB format can be used for positioning complex graphics. Currently this requires manual insertion of the “position: absolute” property in the XHTML code.

What’s Under the Hood?

Similar to web pages, the EPUB format is based on the eXtended HyperText Markup Language (XHTML, Figure 3). The text is contained in .xhtml documents, while formats are determined by Cascading Style Sheet (.css) files. EPUB is also a compressed file format.

How Do You Make EPUB?

EPUB files can be made with text editors and wordprocessing software or with page-layout programs like Adobe InDesign and QuarkXPress. The following procedure shows how a sample EPUB was made in InDesign.

Making an EPUB may be difficult to get used to if you are used to designing pages, because you have to give up control of the pages and allow the eBook reader to make them—something like an autopilot on a plane or the cruise control on a car. A major difference between printed pages and PDFs is that an InDesign document for EPUB should only have one text box per page. The export process will not recognize multiple objects on a page, such as picture boxes with captions or sidebars with multiple picture boxes. For this type of format, PDF is more suitable.

1. Create a document. The document size doesn’t make much difference because the size of the pages is determined by the size and orientation of the eBook reader. Include an automatic text box in the document. In this short example (Figure 4), we used a page size of 6 inches (to approximate the width of an iBook) x 36 inches, something like an ancient scroll. Since the page size does not matter, the long page allowed viewing the entire content in one long document.

2. Create styles. Use a separate paragraph style for each header and body style that you want to use in the document. Before starting, keep in mind which headers you will want to include in the table of contents. The following styles were used for the sample document (all are paragraph styles unless otherwise specified):

• Body (12-pt. Palatino, 12 pt. space before paragraph)

• Heading 1 (18-pt. Palatino Bold, RGB colour green)

• Heading 2 (14-pt. Palatino Bold, green)

• Picture (centered)

• Caption (12-pt. Palatino Italic, centered, keep-with paragraph before)

• Heading Inline (character style, 12-pt. Palatino Bold)

3. Add photos. Photos need to be inserted inline with the text, not placed in separate text boxes (Figure 5). To do so, select the picture box and insert into the text using the Text tool. If you want to put a photo with a caption, group the photo’s picture box and caption’s text box together and place both inline with the text, or set the caption’s paragraph style to “keep with” previous paragraph (which is the picture). Separate paragraph styles (e.g., “Image,” “Caption”) are useful to centre images and captions. The default layout of photos will be positioned between lines of text. To wrap text around photos, you have to manually insert the “float” style into the HTML code (Table 3).

4. Create the cover. The cover needs to be 100% raster, which will be done automatically by InDesign CS5.5. The cover can also be created as a separate image file and attached to the EPUB at the time of export.

5. Create the table of contents. Most eBook readers have a table of contents (TOC) button that displays the major headings, which are interactive. When the user presses on a topic, the eBook will flip to that topic. To create the TOC, set up a Table of Contents Style (Layout > Table of Contents Styles) in InDesign, designating the heading styles you want to be included. On export, InDesign will create a TOC that will appear when the user presses the TOC button (Figures 6, 7).

Editing EPUB

EPUB is trickier to edit than are word processing or page-layout files because they are compressed archives with .xhtml, .css, and other file types. The main reasons for editing an EPUB file are to create runaround text and style tables. The best way to edit an EPUB is using an open-source editor such as Google Sigil (http://sigil.google.com).

Skills Valuable in Producing EPUBs

A designer or production operator who creates EPUBs will find it valuable to be familiar with Adobe InDesign or other page-layout program, especially the EPUB export functions and controls (Table 2). Knowing how to create paragraph and character styles is also important, as these will streamline the typesetting process and allow the table of contents to be automatically created upon export. Knowledge of the Table of Contents feature and Table of Contents Styles is useful. These features set up an automatic table of contents that includes text of specified paragraph styles. Finally, knowledge of HTML and the EPUB format is helpful in tweaking the layout.

Profiles of EPUB Producers

Erin Mallory, Manager, Cross-Media Group, House of Anansi Press

(www.houseofanansi.com)

Erin is responsible for EPUB production at House of Anansi, which publishes for both adult fiction and non-fiction and children’s picture books and novels. She graduated with a Certificate in Publishing from Centennial College and has held positions in traditional print design and production. She says she learned about the EPUB format on her own and was mostly self-taught.

Erin feels that EPUBs are appropriate mostly for text-heavy books, but Anansi is using the fixed-layout EPUB format increasingly for children’s picture books that are intended for viewing on the iPad.

She points out that fixed-layout EPUB has some characteristics in common with PDF, but EPUB is the only format that can be sold on the Apple Store. It can include features like embedded video and the ability to highlight the text in eBooks with audio narration.

Erin feels that the biggest growth segment for EPUBs will be in fiction, romance, sci-fi, fantasy, and mystery novels.

As far as EPUB production, Erin feels that the most effective method is to export EPUB from Adobe InDesign. She points out that major improvements have been made in the EPUB export feature of CS5.5 and CS6. But one feature she would like to see is a one-click export option for the MOBI format of the Amazon Kindle.

Erin feels her biggest challenge in producing EPUBs is getting the documents to look their best on all eBook readers.

Erin points out that there are hundreds of different eBook vendors through which publishers and authors can sell their eBooks, but the most common in Canada are Amazon, Kobo, and Apple. To sell files through Kobo and Apple, she points out, “they must be in the EPUB format and they must be valid EPUB files, which means that you have validated them with one of the approved validation tools, like EPUBCheck. As for Amazon, they only sell files in the Mobi or KF8 (the newest Kindle format that released with the Kindle Fire tablet) formats, but publishers and authors can actually upload their EPUB files if that is all they have, and Amazon will convert them to the Kindle format. No matter which vendor you are supplying your files to, the files will always be put through the vendors own approval processor before they are allowed to go live on the site.”

Nic Boshart, Manager of Technology, eBound Canada

(www.eboundcanada.org)

Nic is technology manager for eBound Canada, a non-profit trade association that collects and disseminates information on electronic file formats and distribution methods. He studied for the Certificate in Publishing from Ryerson University’s Chang School of Continuing Education.

Nic has always been interested in publishing and began with traditional print, being a partner in the Invisible Press. He began learning about eBooks in 2009. Today Invisible Press produces EPUBs for KOBO, Amazon, and libraries.

Nic feels that the biggest market for EPUBs is novels and short fiction. Thanks to the fixed-layout EPUB format, he is seeing an increasing number of picture-intensive books, including children’s books, cookbooks, and textbooks.

Nic feels that the best ways to learn about EPUBs is through self-study online and by attending conferences such as the Tools of Change for Publishing Conference (www.toccon.com). He recommends that service providers and publishers who are interested in offering EPUB services hire a dedicated production person. Skills he considers valuable in EPUB production include understanding HTML coding for manually editing EPUB files and understanding regular expressions for making global changes throughout a document.

Nic feels the biggest challenge in producing EPUBs is understanding that they will not look like books.

Laura Brady, Brady Typesetting

(www.bradytypsetting.com)

Laura Brady runs a typographic shop specializing in EPUBs. She graduated with a degree in history and got interested in publishing in the late ’90s. She supplemented her knowledge of page layout and production by taking courses and seminars.

Laura says that most of her work is in the production of fixed-layout EPUBs, which require considerable manual work. She also feels that the CSS style sheets created by EPUB production programs are not the most efficient, so she hand-codes more effective CSS specifications for her publications.

While Laura specializes more in the production of EPUBs and doesn’t do any marketing, she feels the market for EPUBs is “going through the roof.” She cited a recent “Digital Bookworld” survey that says 67% of adults surveyed have read an eBook.

In addition to hand-coding fixed layouts and their accompanying style sheets, Laura says her biggest production challenge is “device fragmentation,” or getting the EPUB to look as intended on different devices. She owns the most popular to do quality control on her EPUB files.

Laura points out, as did our other correspondents, that EPUB files are not intended to be replicas of the printed page, as is PDF. She points out that the main advantage of the EPUB format is its elastic pages and ability to adapt to different eBook readers and apps.

Conclusion

While EPUBs have become popular and their production has been simplified by tools like Adobe InDesign’s continually improving EPUB export feature, it’s obvious that producing high-quality, commercial EPUBs still requires a lot of skill and expertise—not unlike the typographers and colour scanner operators of the last century.

Further Reading

Castro, Elizabeth. 2011. Elizabeth Castro’s EPUB: Straight to the Point. Peachpit Press.

International Digital Publishing Forum, www.idpf.org

W3 Schools (www.w3schools.com), reference on HTML

Acknowledgements

The author gratefully acknowledges Erin Mallory, Nic Boshart, and Laura Brady for their informative interviews and for sharing their insights on EPUBs.