Documents of type PDF can become very large when several external objects such as images are imported. Therefore a user must be aware of how to compress a PDF file. Even PDF files with just large text data can be further optimized and compressed. This should be done when bandwidth is a bottle neck of the network and to save disk space.
PDF (Portable Document Format) is a platform independent document file format, files of which can be executed on any Operating System. It is also versatile and mainly acts as a container for several types of objects such as text data, images, etc.
The first technique of how to compress a PDF file is pretty simple. The user simply needs to download any one of the several third party PDF compressing software. They are either paid software for commercial use or freeware for home use. Most of the paid software achieves a fairly good compression ratio.
Next method on how to compress a PDF file is by implementing several compression algorithms such as LZW, RLE, BZIP, etc which will compress the PDF file or archive it. These algorithms can be either lossy (loss of data while compression) and lossless (no loss of data). They reduce data redundancy in the PDF file data and replace a single data with that instance.
One of the most important methods on how to compress a PDF file is to compress and optimize the images in the PDF file. High quality images can be re-imported after converting it into a JPEG or JPG file. This reduces a lot of file size, when there are many images in the document. Reducing the color depth and blurring or softening the image also compresses PDF files. Print quality must also be optimum (300 DPI for normal printing). Image size is optimum when it is equal to the maximum window frame size of the document. Vector images or Vector type texts can be compressed by down sampling it. Hence these simple techniques on how to compress a PDF file can be very useful in many occasions such as to save valuable disk space and to make email attachments faster for uploading.