The best PDF compression setting depends on how the file will be read. A scan with large photos has different needs from a form with tiny text or a chart intended for print. Start with a copy, then judge the result at the size your recipient will use.
Resolution and JPEG quality do different jobs
Resolution controls how many pixels are used to render each page. Image quality controls how much JPEG compression is applied to those page images. Reducing either can make a file smaller, but thin lines and small letters can lose detail. Raising both can create a clearer page and a larger file.
Choose a practical starting point
PDFMochi offers Low resolution at 96 DPI, Balanced at 144 DPI and High at 192 DPI. Low usually favors smaller screen-sharing copies. Balanced is a reasonable first try for everyday viewing. High can retain more visible detail when small print matters, although it may produce a larger PDF. JPEG quality also has Smaller, Balanced and Higher quality settings; compare results rather than assuming one combination fits every file.
Review the result before sharing
- Keep the original PDF.
- Make a copy using a starting setting that fits your purpose.
- Check the smallest text, thin table lines, charts, stamps and signatures at normal size and zoom.
- Compare the resulting file size with your sharing limit.
- If the page looks soft, increase the resolution or JPEG quality. If the file grows or looks worse, keep the original and try another approach.
Know the image-based trade-off
The PDFMochi compressor renders each page as an image and rebuilds the file. Text is no longer selectable or searchable, and links, form fields, accessibility tags and digital signatures are not preserved. This method is intended for visual sharing copies, not signed, searchable, accessible or archival originals.
Frequently asked questions
Which setting makes the smallest PDF?
Low resolution and lower image quality often favor size, but the source file affects the result. Inspect the output before sending it.
Why did my PDF get larger?
The original may already have efficient images, or the chosen resolution and quality may create more data than the source.