There are multiple eBook formats available for readers, and the key question is, How do you choose the right one?
Modern eBook readers usually support a number of formats when it comes to displaying digital documents; however, there are three key formats that dominate the market. First is the EPUB which is the most popular format that is also used by most of the big players. For example, Amazon works with the KF8 format. Next is the PDF which is used as an alternative but has its own limitations, like the lack of platform optimization, making it a rigid layout that does not fit onto a display screen. Apple, however, insists on its own eBook format called iBooks. This management software for the Mac, iPad and iPhone also supports external file formats like EPUB or PDF.
EPUB 2 remains the most common format for eBook conversion because of its broad support across retailers, distributors and devices. But not all EPUB files are created equally. Paying attention to the details that ensure the best reading experience is extremely important. For example, conversion tools should prevent errors that eBook buyers frequently flag in their online reviews – such as two words joined together or one word still divided by an end-of-line hyphen, broken paragraphs, question marks, boxes in place of accented letters, symbol characters, lost text formatting and no table formatting.
Reflowable conversions should be device-optimized to ensure a consistent reading experience across eBook readers and apps. Images and file sizes need to be optimized for legibility and speedy downloads, respectively. Hyperlinking of internal and external cross-references, including indexes (to physical page or a specific point in the text), notes (bidirectionally, so that readers can follow the cue and still come back to the text), figure and table citations and URLs that point to a valid web page.
Amazon Kindle: KF8 with region magnification (Kindle Panel View for comics and text/image pop-up for illustrated books)
Barnes & Noble NOOK: EPUB for NOOK Kids, with text magnification and an audio track synchronized to page turns and PagePerfect for other titles
Kobo: EPUB 3 with audio synchronization or simply page images
Google Play Books: EPUB 3 with audio synchronization and integrated video and audio files
When design and meaning are closely linked but a fixed-layout facsimile of the printed page does not deliver an optimal reading experience, we offer conversion to the iBooks Author format as an alternative. This conversion can carry over design elements of the printed book or can be completely reimagined for the iPad screen by our instructional and interactive designers. The format also makes media embedding more seamless than in an EPUB 3 file and extends the potential for interactivity, using ‘widgets’ built into the software or designed specifically for each book.
In some environments, including the classroom, PDFs remain a viable alternative to the EPUB eBook, and their utility to readers can be increased in a number of ways. We regularly enhance PDFs with bookmarks, internal and external hyperlinks, and audio/video content for distribution via the web. We can further improve the accessibility of PDFs to screen-reading and text-to-speech systems by tagging the structure and reading order of content and providing alternative descriptive text for images.