How to Optimize InDesign Files for Printing: Size Reduction Strategies

The usual workflow for printing is to export to PDF, using a very specific PDF standard/profile to match the printing process being used. Besides being the way to send "press ready" files to a commercial printer, it pre-processes things like very large source files and color models into a consistent and often reduced-size print file.

If you're trying to print either very large projects or ones with very large image or content files (well beyond the nominal 300ppi used for print), then any link in the chain from system to RAM to hard disk space to print driver to printer can choke on the amount of data. Export to a correct PDF standard bypasses all of that and often gives better results.