How PDF Compression Works
Learn how image recompression, downsampling, font data, metadata cleanup, and object streams affect PDF file size.
- how pdf compression works
- pdf optimization
- image compression
- downsampling
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The Main Source of Savings
Images are usually the largest part of a PDF. Compression can reduce image quality slightly, lower unnecessary resolution, and use more efficient encoding. A scanned report often shrinks more than a text-only contract.
Cleanup and Optimization
PDFs can contain duplicate objects, unused thumbnails, editing history, embedded fonts, and metadata. Optimization removes or restructures some of that data so the file is easier to store and transfer.
Why Results Vary
A file that was already optimized may not shrink much. A scan with full-resolution photos may shrink dramatically. For the nontechnical overview, see what PDF compression is.
Where to Go Next
For the complete topic map, start with the PDF compression guide. When you are ready to reduce a file, open Compress PDF and export a smaller copy in your browser.
If your output is still too large or looks blurry, use the compression troubleshooting guide to narrow down the cause.