The standard PDF is a static format – i.e. it is not text, but an image of text and preserves the original formatting of the document the way it was supposed to look in print, including graphs and charts.
It does not display well on small screens – for example smartphones or e-book readers with screens smaller than 9”.
Tablets usually handle PDF well and allow for more flexible re-sizing options.
A way to improve the readability of PDF documents on a portable reading device with a small screen is to convert them to reflowable electronic formats.
A number of applications can do that, as long as the PDF file is not protected by a digital lock (DRM).
Most of the Library's PDF e-books are not protected by DRM.
Being reflowable means that when the text size is either increased or decreased, the text readjusts to fit the screen. The most popular reflowable formats are:
EPUB is a format standard for digital publishing that offers interoperability between operating systems, computers, and reading devices. Its key characteristic, namely being reflowable, makes it very suitable for mobile reading on a small screen.
EPUB is compatible with most e-readers (a notable exception is the Amazon Kindle). A number of reading apps allow users to read EPUB on smartphones and tablets – example BlueFire Reader, available on the App store and Google Play.
AZW (Kindle format) is the Amazon proprietary format used for Kindle e-books. It is compatible with the Kindle e-reader and Kindle apps for smartphones and tablets.
MOBI (or Mobipocket) – universal e-book reader for PDAs. Compatible with Blackberry, Palm, Symbian OS.
Some examples of applications capable of converting PDF into refloawable formats are:
eReader Formats is an application that allows you to convert a ScienceDirect article in ePUB or Mobi before loading it to a mobile device such as Sony Reader, Amazon Kindle, iPhone, iPad, B&N Nook, etc.
Calibre - a free and open-source e-book management application that allows for conversion of non-DRM protected e-book files between different formats and well as managing this content and syncing it with portable reading devices.
...as well as number of other free or paid applications available on the web.