Shrink PDF File
In a typical workday, most of us have to deal with a large number of digital documents in PDF format, in creating, editing and transferring them through the Internet. PDF documents are content rich, as they hold text, different fonts and graphics and make the presentations more interesting and easy to understand. However these elements also make the file size huge- it can be quite a pain to store or send them online. A compressed version can save storage space and takes less time to be attached with emails. Compression here means reduction in the file/data size. This also makes it less time-consuming for the recipient of the email to download the attachment.
Data compression of PDF files can be done either by compressing only the data content of the entire unit. Simple techniques such as removal of extra space characters and use of a single repeat character for a particular string of characters such as a word can shrink the file to half the original size. This is achieved by programs that use algorithms to fix ways to compress and decompress data. The strength of the algorithm is crucial to the quality of compression.
PDF files already come with some compression functionality built in, as they are designed to be loaded with graphics and other space consuming stuff.
Compression techniques used on PDF can be either lossy (some information is lost in the compression process) or lossless (all the content can be restored on decompression). Lossy algorithms like JPEG compression can be used to shrink image and audio files, but they are not useful for text and program files. The latter need lossless compression algorithms.
To shrink PDF files to the best extent possible, prepare the bitmap images to be inserted in such a way that the dimensions are minimized. Find the best quality images and use black and white images wherever possible. Turn off thumbnails. Vector based graphics generally work better than bitmap graphics. Avoid using too many fonts, as each additional font takes 40k in getting embedded. Wherever possible, flatten the form fields, although this merges the data with the page and renders the form unusable. RGB color space works better for shrinking than CMYK. When color is not really needed, think of using grayscale.