First identify what makes the PDF large
An image-heavy PDF scanned at high resolution has different compression opportunities from a text-based PDF with embedded fonts. Before processing, check file size, number of pages and whether words can be selected. If the document consists mostly of crisp vector text, a raster-based method can make the file larger rather than smaller.
Understand raster-based PDF compression
Docvelio's browser PDF compressor renders pages as images and stores JPEG representations in a new PDF. This may help large scans, but it changes how the document behaves. Searchable/selectable text, form fields, hyperlinks, bookmarks and some accessibility structure can be lost. It is not the same as optimizing the existing PDF objects while preserving everything.
Choose the right quality for the actual use
For a document read mainly on screen, moderate image quality may be sufficient. For diagrams, small type or documents that will be printed, higher quality is safer. Test one representative page and zoom in to see whether punctuation and fine lines remain legible. The smallest file is not necessarily the best file.
Alternatives that preserve more information
If the problem is just a few oversized photographs, reduce their size before combining them into a PDF. If you need searchable text or filled forms, use a specialist PDF optimizer that retains those objects rather than rasterizing. Always keep a copy of the source and compare file size, legibility and interactivity after compression.
Steps you can follow
- Check whether the original PDF is scanned or contains selectable text.
- Set a quality level and run the compression only if losing selectable text and form interactivity is acceptable.
- Compare output size, zoomed text, links and page count with the original before replacing a file.
Frequently asked questions
Will compression always make my PDF smaller?
No. Rasterizing small or text-heavy PDFs can increase their size.
Will my PDF stay searchable?
Not with this specific raster-based process. It can turn text into page images.
Check before sharing: Keep your original file and review each download.