The Portable Document Format - PDF.

This article demonstrates how documents prepared in hypertext or word processor format can be saved in portable document format (PDF). These files are self-contained documents that that have the same appearance on screen and in print, regardless of what kind of computer or printer are used, and regardless of what software package was originally used to for their creation. PDF files are compressed documents, invariably smaller than the original files, hence allowing rapid dissemination and download.

Portable Document Format (PDF - Adobe) was created in order to allow formatted documents to be widely distributed regardless of whether specific fonts or postscript files are available on the user's system.12 PDF files have the ability to internally embed specialised fonts, images, colours and formatting regardless of the application and platform used for the documents’ creation. This ensures that as long as the user has the ability to read PDF files, documents will be viewed exactly as formatted by the original authors, with both appearance and content integrity.

Moreover, for online viewing, the browser plug-in is stable, easy to use and available for download. PDF files also allow the easy distribution of large documents, and the indexing facility inbuilt in the PDF format can create a fast lookup system. PDF is one of the most portable file formats available, and does not require a browser for viewing, only the Acrobat Reader which is free and compact. PDF files can also be viewed on Palm devices. The PDF format has been found to be very reliable, and is used for the dissemination of official documents by governments worldwide (Adobe Acrobat and PDF - essential tools for e-government http://www.adobe.com/government/images/pdf/acr_egov.pdf).

Tables of contents, articles and announcements (such as lists of conferences) should be made available in PDF format. The conversion of hypertext documents, complete with graphics and tables, to the PDF format, can be most easily carried out with the Adobe PDF Maker software. This program allows the direct conversion of Word documents to the PDF format from Word itself (and also other Microsoft Office software such as Excel and PowerPoint) by using one of two alternatives:

PDFWriter: generates PDF files in a one-step process with preset default settings. The resulting files have only basic functionality and this method is only recommended for the creation of simple, small text files that do not contain graphics, tables or links.

Acrobat Distiller: generates PDF files using a two-step process in which the Word file is first converted to high-quality PostScript output (as if printed to a file instead of to a printer), and then to PDF. This method is recommended as it allows the user to set a variety of job options that enhance both appearance and functionality of the output PDF files, and easily converts documents containing graphics, tables or links.

The following steps are used:

The relevant hypertext document should be loaded into Microsoft Word – all recent versions of Word (97, 2000, XP) are inherently able to read hypertext documents, complete with graphics, tables or links.

The document should then be saved in native Word format. This allows the document to be formatted including left and right justification and page setup. The actual page length is now known, and page numbers and document name in header/footer can now be inserted.

The Acrobat Distiller is launched and PDF file created. PDF files converted from Word are cropped to match the Word page size and can be immediately viewed by Adobe Acrobat or Acrobat Reader.

Output options include the ability to embed hyperlinks. The generated output can also be screen optimised, print optimised or press optimised, with increasing levels of resolution and display detail, at the cost of increasing the output file size. For example, this document output in the above three optimisation levels, generated file sizes of 312 kb, 405 kb and 412 kb respectively.

A prominent link from the hypertext document to the PDF file should naturally be made available, and it is courteous to state the approximate size of the PDF file, perhaps as part of the link itself. The intermediate Word document should be retained for backup purposes. The output PDF file may be reduced in size by the substitution of logos with text where possible and in this respect, tables can be useful (figure 1).

Figure 1

a: Journal logo for online use - transparent gif file b: Journal logo for PDF output - as a table