Designing eBooks for Different Devices
You design Adobe Acrobat eBooks in a word processor or page layout program and then convert their documents to PDF. You can then perform any last-minute tweaks, such as adjusting text flow or linking multimedia objects, in Acrobat and then view your final product either in the Adobe Acrobat eBook Reader on your computer or laptop or on a Palm OS or Microsoft Pocket PC handheld device.
PDF files come in three document structure flavors — unstructured, structured, and tagged. Structured PDF files enable you to convert or repurpose a PDF for another format, such as RTF (Rich Text Format), while retaining much of the original page layout and reading structure. Tagged PDF files have the highest degree of success in retaining their original formatting when converting to RTF and are also able to reflow text, which is not the case with unstructured or structured PDF files. For the purpose of creating eBooks, then, you should always use tagged PDF files because they offer the most flexibility when it comes to viewing the final product on the greatest number of viewing devices.
The following programs enable you to convert their documents to tagged PDF files in order to build an eBook:
- PageMaker 7.0 (Windows and Mac OS)
- InDesign 2.0 (Windows and Mac OS)
- Microsoft Office (Windows, versions 2000 and XP only)
The Adobe Acrobat eBook Reader was developed to provide a means of viewing PDF eBooks on a computer screen or laptop. Because of their size, computer screens are well suited to display graphically rich page layouts that re-create the reading experience of a printed book. For designing these types of eBooks, page layout programs (PageMaker, InDesign, or FrameMaker) are the best tools to use. In addition to allowing complex page layouts, their ability to create tagged PDF files adds a higher degree of accessibility for visually challenged users viewing PDF files in Acrobat eBook Reader.
Graphic size and page layout are definitely restricted by the screen size of handheld devices so it's better to develop eBooks that you want to view on those devices in Microsoft Word, which is text based and has Acrobat 5 features built in that enable you to create tagged PDF files with the click of a button.
Here are a few considerations to take into account in order to optimize eBooks designed for Palm OS or Microsoft Pocket PC handheld devices:
- Graphics: With handheld device screen resolutions running between 160 x 160 for Palm OS devices and 320 x 240 for Pocket PC devices, graphics must be optimized for the target screen size if used at all. Note that while the majority of Pocket PC devices in use have color screens, many more Palm devices are out there right now without color. You could consider preparing your graphics in grayscale (thus creating a smaller file) for this reason.
- Fonts: Use the common Base 14 system fonts that are installed on your computer. These typefaces have been optimized for on-screen viewing and produce the best results when viewed on a handheld device.
- Paragraphs: Separate paragraphs with an additional hard carriage return for clearer visibility on the Palm handheld screen.
- Conversion settings: For grayscale Palm handheld devices, Adobe suggests some slight changes to the eBook job option in the Acrobat Distiller. You can get the specifics on creating a custom job option for these handheld devices on this online page.
Adobe recently released two free products, Acrobat Reader for Palm OS and Acrobat Reader for Pocket PC. You can download these products at this URL.
The Acrobat readers are applications that are installed on their respective handheld devices and are designed to accommodate their specific screen characteristics. In addition to the reader software, each product includes a Windows desktop application for preparing and transferring a PDF to a user's handheld device. The Palm OS reader includes a HotSync conduit, and the Pocket PC version includes the ActiveSync filter, which has an added feature that attempts to create tags from untagged PDF files prior to uploading them to the Pocket PC handheld device.