A PDF is more than its page count
Two documents with the same number of pages can have very different sizes. A short scan with high-resolution photographs may be larger than a long text report. Embedded images, fonts, repeated objects, and the way the file was saved all contribute to the total. Page count alone is not a reliable way to predict how much a compressor will help.
What local optimization changes
Folio’s Compress PDF tool rewrites the document with compressed object streams. This can reduce structural overhead while retaining the existing text and image resolution. It does not downsample photographs or rasterize pages. The benefit depends on how the original PDF was produced. A file that was already saved efficiently may show little or no reduction.
When the original is the better result
If optimization produces a larger file, Folio says so and makes your original available instead. That is an honest outcome rather than a processing failure. Running the same file through the same optimization repeatedly is unlikely to keep reducing it. For an image-heavy document, exporting a smaller version from the original application may be more effective. Check its image-resolution settings and preview fine text carefully.
Choose readability over a target percentage
Before sharing, open the result at a normal reading size and zoom in on small text, charts, and signatures. Keep links and selectable text useful whenever possible. If an upload service sets a strict size limit, splitting a long document into useful sections may be more appropriate than making each page hard to read. Keep a full-quality original so you can produce a different version later.