What’s the Difference Between EPUB, DPS, and PDF?

David Blatner

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I saw this question on twitter recently: “What is the fundamental difference between EPUB3 and Adobe DPS?” and I realized that I’ve been asked this a lot recently. For example, we had an EPUB track and a DPS track at The InDesign Conference and a lot of people wrote in to ask which one they should attend. Plus, how are those different than PDF? And what’s the deal with FXL and SWF and other digital formats?

So, in hopes of clearing the air a bit, here’s My Answer:

Document vs. App

Do you want to be a software developer or a publisher? Software developers make apps (or applications, or programs, or whatever you want to call them). Publishers publish documents. Documents are files that can be viewed in a Viewer application.

So, for example, when you create a PDF file you’re making a document that is going to be viewed in Acrobat or Reader or Preview or a Web browser, or some other program. Similarly, when you export an EPUB file, you are making a document.

The great thing about documents is that you can move them around: you can email them, post them on a server, put them in a store for downloads, save them to disk, archive them, and so on. As long as there is a viewer, you can read them on any device: desktop, laptop, web browser, iOS, Android, Linux, or whatever. Even better, you can distribute them without someone else (e.g. Apple) saying it’s okay.

The great thing about apps is that they are software, so they can do things that only software can do: you can sell them in an app store like a game, you can have in-app purchases, you can optimize for native software speed. But apps have to play by app rules: it’s harder to publish them, they run on just one device type (an iOS app cannot run on Android, etc.), you have to get permission from Apple to publish it to the iTunes store, and so on.

But a strange thing has happened over the past few years: there are a lot of apps that look and act like documents; and some apps allow “issues” that are downloaded and read like documents inside the app (for example, monthly magazine subscriptions). Conversely, documents have gained new powers to act like apps. For example, you can put interactivity into a fixed-layout EPUB file (FXL) and some PDF files that make them interactive, like an app.

DPS

If you want to turn your InDesign document into an app, you’ll need special software and a service. Adobe Digital Publishing Suite (DPS) was the first to offer this, and remains the most popular service today. Make no mistake: DPS is not an authoring tool. DPS is, at its heart, an app creation and distribution service. A lot of people tie DPS to InDesign, but that’s just because they’re both from Adobe, and InDesign was the first tool to connect to DPS. You can now use a wide variety of tools and products (even PowerPoint!) to author for DPS.

Adobe does offer some tools that help you add some DPS interactivity to your documents, and to help get your InDesign document into their DPS system, but not all InDesign features are natively supported in DPS at this time.

Behind the scenes, the DPS system converts your documents into actual software apps. A major part of the DPS ecosystem is its analytics system, which provides insight into what people are reading, how long they’re reading it for, what they tapped/clicked, and more. It’s impressive.

Other App Makers

Fortunately, there are also a number of other players in the “InDesign to App” market, including Twixl and Aquafadas. These companies also offer alternative paths to converting InDesign documents to software apps. And, even better, in many cases they’re very competitive, especially for small to mid-sized companies. (Adobe is currently focusing their DPS efforts on “enterprise” customers—national magazines, larger companies who produce interactive sales materials, government agencies, and so on.)

Web Apps and Web Viewers

There’s a middle-ground, hybrid solution which is also very interesting: Web Apps or other HTML5 solutions. For example, you can create a richly interactive experience that works in a Web browser with eDocker or ajarproduction’s in5, both of which convert your InDesign layout to HTML5. Both systems offer a wide variety of options for what to do with those apps/docs.

For example, at this years’ PePcon: The Print + ePublishing Conference, Jerry Silverman showed you could export a document with in5, then use Adobe’s PhoneGap (which is part of a Creative Cloud membership) to quickly and easily convert the HTML5 package into native iOS and an Android apps.

EPUB, PDF, and other Document Formats

While people get so excited about making apps, I argue that making documents is often preferable for most publishers and creative pros. For example, many folks have been incredibly frustrated after spending dozens or hundreds of hours of hard work on an app, when they are rejected by Apple’s app store for being too much like a book. Apple doesn’t want just a little bit of interactivity; they want immersive, app-like experiences! It’s tricky.

Similarly, it’s much harder to create an app than a document. Making the interactivity in InDesign is fun, but when it comes to taking it the next step — getting it into the app store — well, I heard an publishing IT guy recently call the process “brutal.” Of course, if you’re doing a multi-issue app, then you only need to submit the app once (well, until the OS changes and then you typically need to provide updates), and then each “issue” is easier.

But compare that to exporting and distributing a document, such as a PDF file. You choose File > Export. Done.

The problem with PDF files is that interactive features don’t work very well in them on some devices. For example, buttons and videos often don’t work on iPads; and if you don’t have Flash on your computer, even Acrobat can’t manage a lot of the rich media you can put into a PDF (like audio or video).

Fortunately, there’s a new kid on the block: Fixed Layout EPUB (FXL). You can use the newest version of InDesign to make highly interactive FXL files (with hyperlinks, video, buttons, animations, slide shows, and so on), and these FXL files are documents that you can distribute in many ways. You can publish them in Apple’s iBookstore, or sell them or give them away on your own web site… you can make awesome sales slide presentations and put them on your sales staff’s iPads; you can create children’s books and sell them in a variety of stores…

FXL isn’t perfect. It’s still a relatively new format. You can view it on Mac and Windows and iOS and Android, as long as you have modern EPUB3 reader software. For example, Apple’s iBooks, Adobe’s Digital Editions software, Kobo apps, and the Readium Chrome extension, are all free options for reading FXL files. You cannot play it on Kindle because Amazon does not support EPUB (they have their own proprietary format).

How to Learn More

We are in the middle of a publishing revolution and nothing is stable. You can stay current and learn “how to” publish in all these ways at PePcon: The Print + ePublishing Conference. I hope to see you there!

Other links for learning more about DPS and FXL:

• Anne-Marie Concepcion’s Creating Fixed Layout EPUBs with InDesign CC video title at lynda.com
• Mike Rankin’s Adapting a Print Layout for Digital Publishing video title at lynda.com
• Adobe Drops DPS Single Edition Support from Creative Cloud
• More InDesign DPS tips