How to Compress a PDF Without Ruining It
Start by identifying what makes the PDF large
PDF size usually comes from high-resolution scans, embedded photographs, duplicate image resources, fonts, or unusually complex page content. A 50-page text report can be smaller than a two-page brochure filled with high-resolution photography.
Use raster compression for scan-heavy PDFs
If most pages are scans, rendering pages to optimized JPEG images can cut file size dramatically. The tradeoff is that selectable text can be flattened unless OCR is run again afterward.
Keep enough resolution for the destination
Email attachments generally do not need print-production resolution. Forms and portals usually need legibility more than perfect image detail. For contracts, legal filings, or records, inspect the compressed output at 100% zoom before deleting the original.
When not to over-compress
Small text, signatures, diagrams, barcodes, and fine line art can become difficult to read. Use lighter compression for those files.