Portable Document Format (PDF) files are file formats in which many kinds of files like text, graphics, images and videos are all encoded in a single file in a chronological order. It consists of a variety of data and also large amounts of information and hence is ideal when it comes to file-sharing.
Shrinking PDFS file is a term that is heard very often as the PDF files tend to be bulky, owing to the amount of data that is stored in the file and also the variety of data stored. The PDF files can be shrunk by either using a software or by other means.
Methods behind shrinking PDFs
The methods used to shrink a PDF file without using a software are by optimisation of the data stored in the file. Unwanted parts of the file like bookmarks, tags, comments and the like are deleted and the resolution and quality of the images and videos are reduced, thereby reducing the size of the files. The variation in the style and type of the fonts is reduced and the background gradients are minimised so that the amount of encoding done is reduced. The metadata is also edited and rewritten in such a way that lines of encodings are not repeated and the like.
Software for shrinking PDFs
Softwares can also be used to shrink a PDF file. These softwares use lossless or lossy algorithms by means of which the file size of the PDF is reduced, thereby shrinking the PDF file. Lossless algorithms are means by which the file can be decompressed back to the original form without loss in the tiniest detail in the file whereas the same cannot be said for lossy algorithms. The methods like deletion of unused parts and reduction of image and video quality fall under lossy algorithms.
Lossless algorithms to shrink a PDF file include zip, rar, etc which are familiar. They decrypt the file into binary sequences and ASCII equivalents of the binary sequences are stored in the file, thereby reducing the amount of space occupied. These files can also be decompressed back to the way it was before compression without any loss in data.