PDF (Portable Document Format ) format is already optimized and he de facto standard for document publishing on the internet and other media.
A PDF file is often a combination of vector graphics, text, and raster graphics. The basic types of content in a PDF are:
* text stored as such
* vector graphics for illustrations and designs that consist of shapes and lines
* raster graphics for photographs and other types of image
Because all graphics and other stuff PDF file is optimized. You can use program such as Winzip or 7-Zip (or command line utility winzip/zip) to package and compress a pdf file. My personal experience shows that you will not gain much benefit from compressing a PDF file as compression ratio is very small.
I’d be interested to hear if you have other software program to consider when compressing a PDF (remember it must provide a good compression).