A PDF, or portable file format, is a 1993 ISO standard designed by Adobe systems whose main purpose is to keep document structures intact across machine platforms and viewing applications. This tremendously helps those who want to create documents that users cannot change easily. Various things like copyright material, bills and checks, manuscripts and other similar documents require that they be unchangeable, or at least changeable only by the chosen few. Such security is integrated in the PDF file because of viewing and editing password protection, as well as the embedding of layout and structure data in the document itself.
Why should a PDF be reduced?
A PDF file can be very bulky. Because it tries to retain its layout and design, reading order and structural tags etc, it needs to carry these bits of information along with it and embedded within the document itself. Images and fonts can become exceedingly large in size, and especially the background information about document structure tags, bookmarks and page thumbnails can all add to the size, to say nothing of the content. This is fine for printing, but because it can be very inefficient for transmittal and storage purposes, PDF files require to be reduced.
How is a PDF file reduced?
Various factors go into the planning when you want to reduce a PDF file. Fonts, images, version used, removal of redundant and space consuming material, all these factors can be part of the plan in reduction of a PDF file. Fonts can add 40k each and if they are not correctly used, they can really make the size extremely large. Size also depends on PDF version; as you go up along the scale, more sophisticated later versions create less bulky files. These are some of the methods to reduce PDF file.