Why we use PDF files

PDF (portable document format) is a file type developed by Adobe Systems, Inc. that delivers electronic documents over the Internet with composition and format intact. As you've probably already seen, many Internet-based documents, such as emails and even some Web pages, are pretty dull. The most frequent complaint from users is that type styles, or fonts, are difficult to read. Accurate page layout also is lacking on many sites.

PDF solves these problems, and others, because it allows the author to specify fonts and styles, and to accurately position page elements, so the document has the same rich format no matter where it is opened. You see the document (or image) as the author intended it to look. Millions of documents currently are available as PDF files on the web. The US government distributes most of its electronic documents as PDF files (for example, check out the IRS site at www.irs.gov). If you spend much time on the Web it is worthwhile learning to use Acrobat Reader! PDF also makes document printing much easier.

PDF has another feature that is especially important to website owners, namely the ability to password-protect their images. With PDF the user is free to download and view the images but may not be able to easily extract or print them (depending on author-selected options).