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.
When changes have to be made to the PDF file, it is better to use the Save As option to overwrite the entire PDF file. Otherwise when the PDF is saved by the Save option, changes are appended to the file, and there is a slow and steady accretion of kilobytes. Named destinations are markers that identify locations in a PDF file. This option can be used when the user plans to link a second PDF file to a specific point in the first PDF document. The user can find out whether fonts or images are taking up the most space and make changes accordingly by selecting the Advanced to PDF Optimizer to Audit Space Usage option.
In case of PDF files, compression means image compression. PDF formats are usually designed to compress information as much as possible. To compress a PDF file to the utmost one should insert the bitmap images in such a way that the dimensions are minimized. The user should also look out for the best quality images and use black and white images wherever possible. RGB color space is better for compression than CMYK. When color is not needed one could use grayscale. Additionally thumbnails should be turned off since vector based graphics usually work better than bitmap graphics. Also one should avoid using too many fonts because each additional font takes 40k in getting embedded.
Compressed PDFs help to reduce the file size while maintaining the quality of the original software. Some compression software can also remove text annotations, page labels, bookmarks etc. Some packages also have special graphic interfaces.