Viewing PDF files is easy: just go to the web site of Adobe and download Adobe Reader, a freeware application that can be used to open, view and print PDF files. Adobe Reader is available for various platforms: Windows (from Windows 95 to Vista), Macintosh (MacOS 9.1 to the latest OS X), Unix (Linux, Solaris, AIX, HP-UX) and mobile devices (Palm, Pocket PC, Symbian).
Adobe also sell Acrobat, more powerful software with extra features. This is the software that most professionals in graphic arts use.
Next to Reader & Acrobat, there are other applications on the market that can display PDF files. These applications are usually either geared towards a specific platform that is not well supported by Adobe Reader or the viewers run faster on smaller machines (Adobe Reader is quite a resource hog). The list of viewers is too long so I’ll just list a few:
Several applications including Corel Draw, Adobe Illustrator, can open or import PDF files so they can be used as well for viewing PDF files.
Limitations when viewing PDF files
You should be aware that PDF files are not always displayed exactly like they will be printed or imaged. Even 10 years down the desktop publishing revolution, what you see is still not always what you get.
Below is an overview of the most important limitations:
- PDF files contain contone information meaning that the drawings, images, or colorized text in the file are not screened yet. If you zoom in on a colorized object in a PDF file, you will not see the screened data. This means you cannot check a PDF file visually for moiré artefacts.
- Not all viewers display overprints as they should. Older versions of Acrobat (3 & 4) are not capable of displaying overprints. In Adobe Reader, enabling overprints is hidden in the Preferences. If displaying overprints is not activated and a document has yellow text in overprint on a cyan background, the PDF will display yellow text, even though green text will be printed.
- If a font is missing in a PDF file, Acrobat uses a sophisticated system to emulate the missing font. This sometimes gives the impression that the PDF-file is perfect and can cause differences between what you see on-screen and on the printed output.