PDF and Compression
PDF and compression are two terms that are often heard together because PDF files are compressed the most owing to the amount of data contained. PDF compressors use various algorithms by means of which the space occupied by the file decreases and sharing of the document is made easier. All this happens because when a PDF file is edited, data gets added and the old data is never erased and a lot of redundant code is accumulated in the file. Other factors like bookmarks, images and graphics contribute to the file size too.
Process of Compression
Most of the PDF compression software available work on the metadata of the file. Redundant codes are removed and repetitive codes are accumulated in a place so that space occupied by extra codes is reduced. The software also removes unwanted bookmarks and pointers from the PDF file. The PDF compression software may also edit the content present in the file so as to reduce the size of the file. Unused parts of the file like images and text may be removed and the text may be made into a single font and colour instead of multiple font colours and types. Softwares that also archive the file and thereby compress it are also present and they preferred to the others because data is not lost while compression or decompression of PDF files.
PDF Compression Software
All PDF compression software are tools that help in compression the PDF files. They may use any algorithm and reduce the size of the PDF. The advantage in using PDF compression software is that the process is done automatically and also many files can be compressed in batches in certain softwares. Free PDF compression softwares are available for download throughout the internet. However, what characterises good free compression softwares are their rate of compression and degree of compression. Also, free PDF compression software must be able to successfully compress and decompress a PDF file in lossless algorithms. These factors, along with the other features like data retentivity and degree of document recreation offered are to be kept in mind while choosing free PDF compression software.