PubToo · Guides
How to compress a PDF: scans, text documents and signatures
Understand why scanned and text PDFs compress differently. Choose a suitable mode, then check pages, text, links, forms and digital signatures in the exported copy.
PDFs with the same page count can have very different sizes. A scan usually contains page images, while another document may contain text, fonts, vector artwork, bookmarks and forms. Identify the content before choosing a compression method.
The aim is a usable copy that meets the recipient’s limit. Keep the original, especially when it carries a digital signature, has an archival requirement or will be used for formal printing.
1. Identify the main contents
Zoom in and try selecting a paragraph. An ordinary scan is mostly imagery. Selectable text may indicate a text document, but it can also be a recognition layer over a scanned image, so that check alone does not identify everything inside. Photos, scanned pages and embedded fonts all contribute to size. An already optimized text document may offer very little room for further reduction.
2. Start with a gentler mode
PubToo offers Lossless, Balanced and Smaller PDF modes, with an optional target size for each file. Lossless optimization is a conservative first attempt. For large scans or photographs, compare a Balanced result. Consider Smaller only when the details remain suitable for the intended use.
Reducing the resolution or encoding quality of embedded images may make scanned text and pictures less clear. Inspect small tables, technical drawings and anything intended for formal printing carefully. PubToo does not compress a PDF by turning each entire page into a picture. Its main work is structural optimization and recompression of embedded images, rather than recreating the document’s contents.
3. Review the copy, not just the byte count
Open the export in the reader the recipient will use. Check the first and last pages and those with the most complex content. Matching page counts is only the starting point: review text, table borders, charts and pictures as well.
- Confirm that text selection or search, bookmarks and links behave as expected.
- Compare small lettering, scanned stamps and pale details at normal reading size and while zoomed in.
- For forms, check entering values, saving and reopening the file.
- Check the real file size against the destination’s submission requirements.
4. Handle signatures and archival requirements separately
A visible signature graphic is different from a verifiable digital signature. For a signed PDF, PubToo exports a copy with the digital signature removed while keeping its visible appearance; the original remains unchanged. If the recipient needs to validate the original signature, send the original or follow their process for signing the compressed copy again.
Forms and PDF/A documents follow a conservative structural path in PubToo, but the product does not claim PDF/A compliance for the output. Compression does not replace format validation, text recognition or archival acceptance. Use the appropriate verification process when those requirements apply.
When the target cannot be reached
Further processing may not make an already small or mainly text-based PDF smaller. Keep necessary text readable. Check whether the recipient allows a larger attachment or separate submissions, or export a transmission-friendly version from the original document.
PubToo processes PDFs on the device; this website does not accept uploads for compression. Check the product and support pages for edition status, system requirements and limits. For help, email contact@zinuto.com with the file type, approximate size and error message. Private originals are not needed as the first step.