Checks if the latest and most efficient compression mechanisms have been applied in the PDF document.
Compression mechanisms are used to reduce the file size of a PDF. Previous versions of Adobe Acrobat (2.1, 3.0, 4.0) featured less advanced compression mechanisms; this check allows you to find and correct them.
If your document contains objects which were left uncompressed for a specific reason, for example to preserve metadata, select the option Ignore non-compressed objects.
Enable the Use ZIP compression where applicable checkbox.