Using PDFs

Many publications and electronic journals are available on the World Wide Web in a format known as portable document format (PDF). Various free applications can be used to read PDFs, perhaps the best known being Adobe Reader. Other utilities, for example xpdf for Unix and Preview (built into Mac OS X) are also able to display many PDF files, but some cannot be viewed with those programs and need the Adobe software. A number of other functions may be built into a reader, such as reading the file out loud, extracting the content of a PDF to a text file, or converting it it to a PostScript file. There are other free and commercial applications available, many of which can be also used for generating PDFs - see Wikipedia's list of PDF software for more information.

• Adobe Reader can be found at Adobe UK. You should be aware that there are version differences between the current and earlier versions of Acrobat Reader that may cause problems opening PDFs. Adobe Reader is available for many operating systems and in several languages (although for some the newest version of the software may not be available).
• xpdf (an open source pdf viewer) can be found at Xpdf - Foo Labs.
• There are several web-based applications for producing PDFs - see the Wikipedia article

After installation, you may have to adjust your web browser so that it will recognise PDF files and (if you wish to work that way) open your browser to view them. Alternatively the browser can be set to open the PDF with the Reader or to save the file and use the Reader application to open it later.

Accessibility

PDFs are not the easiest files to use if you have poor vision or use a screen reader - the content can be read out and text can be extracted but often it has then lost its structure and is not straightforward to understand. See Adobe's Accessibility pages for links to documents about accessibility of pdfs from various versions of Acrobat, information to help those with disabilities get the most from pdfs, and specific information for users of some of the accessibility software packages. In addition there are tools for some OSs that make PDFs more accessible or allow saving of the file as XML (which may give the information more structure than plain text).

Configuring to use the reader

The Adobe Reader is already installed and configured for both PCs and Macintoshes on the MCS.

If you wish to read PDF files on your own computer, first check whether the browser you use has PDF reader software already installed, by trying to read a PDF file. If it has not, you need to download the software and install it, following any installation instructions that come with the files.

Depending on the browser, you may then need to configure your web browser to use the reader to display PDF files. To find out, start up the browser and go to a link for a PDF file. If the browser gives a message that an application to read the file is not available, you will need to configure the browser so it knows where the PDF reader is.

In some versions of Microsoft Internet Explorer, when a PDF file is first encountered there will be a query for the location of the application to read it. Once you have located the PDF reader, you can specify that that application is always used for that type of file.

Creating PDFs

There are many easy routes to create PDFs, using PDF Writer or Mac OS X. If you want to make PDFs available on the web, you need to check that the title and hidden information is not misleading. This information is derived from the original file and particularly those files derived from Word may inherit spurious or unintended information.

To edit the title and the hidden additional information (metadata) that is used by search engines, you will need to look at the file with a full version of Adobe Acrobat. This is available on the MCS PCs.

• Open Acrobat and then open the file by going to File > Open or drop the pdf file icon onto the application icon.
• Go to File > Document Properties > Summary. The boxes on this screen give you the opportunity to add title, description (under subject) and keywords. Author can be added for reference but isn't used by any search engine. When you have finished, click OK.
• Go to File > Document Properties > Document Metadata and you will see the metadata the file now holds. Remember to save the file if you want to retain these changes. If you edit PDFs located on web servers in cam.ac.uk in this way and want them reindexed to show the edited information, then put the edited version on the web server and reindex (in web-search go to 'Add URL' to add the URL for reindexing).

In Mac OS 10.5 and later, when you create a PDF the metadata inhertied from the original file is removed and a dialog box allows you to enter the title, description and keyword metadata.

PDFs should also be optimised to reduce their file size - this can also be done through the full version of Adobe Acrobat.

Last updated: November 2011