Specifications

You can read more about Ghostscript at

http://www.ghostscript.com/

and download it from

http://www.cs.wisc.edu/~ghost/

For our current application, PostScript scores very well for consistent high-quality output,

but falls short on most of our other needs.

Portable Document Format

Fortunately, there is a format with most of the power of PostScript, but with significant advan-

tages. The Portable Document Format (also from Adobe) was designed as a way to distribute

documents that would behave consistently on different platforms, and deliver predictable

high-quality output on screen or on paper.

Adobe describes PDF as “the open de facto standard for electronic document distribution

worldwide. Adobe PDF is a universal file format that preserves all of the fonts, formatting,

colors, and graphics of any source document, regardless of the application and platform used to

create it. PDF files are compact and can be shared, viewed, navigated, and printed exactly as

intended by anyone with a free Adobe Acrobat Reader.”

PDF is an open format, and documentation is available from here:

http://partners.adobe.com/asn/developer/technotes.html

as well as many other Web sites and an official book.

Judged against our desired attributes, PDF looks very good.

PDF documents give consistent, high-quality output, are capable of containing elements such

as bitmap and vector images, can use compression to create a small file, can be delivered elec-

tronically and cheaply, are usable on the major operating systems, and can include security

controls.

Working against PDF is the fact that most of the software used to create PDF documents is

commercial.

A reader is required to view PDF files, but the Acrobat Reader is available free for Windows,

UNIX, and Macintosh from Adobe. Many visitors to your site will already be familiar with the

.pdf extension and will most likely already have the reader installed.

PDF files are a good way to distribute attractive, printable documents, particularly ones that

you do not want recipients to be able to easily modify. We will look at two different ways to

generate a PDF certificate.

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