A smaller PDF is useful only if the recipient can still read it. Before changing any settings, keep the original and decide what must survive: searchable text, sharp diagrams, fillable fields or simply a readable scan.

Start with the type of document

Try selecting a sentence in your PDF. If the text is selectable, the document probably contains a text layer. If the whole page behaves like a photograph, it may be a scan. Some scans also have an OCR text layer, so text selection alone does not tell you everything.

In Filestation’s PDF compressor, start with Keep text & page content for a text document. This rewrites the PDF structure without downsampling the pictures. It can produce modest savings, and it may leave an already efficient file unchanged.

Use stronger compression for scans

The image method renders every page as a picture. Choose Balanced first. Resolution controls the number of pixels used to represent the page; image quality controls how strongly those pixels are JPEG-compressed. Lowering both can make small print hard to read.

Grayscale is useful for documents where colour conveys no meaning. Keep colour if highlights, charts, stamps or diagrams depend on it. The image method removes selectable text, active links, form fields and existing digital signatures.

Working toward a 500 KB limit

Enter 500 in the target-size field to ask the compressor to try progressively smaller image settings. The target is a request, not a guarantee. A long document with detailed scans may not fit while remaining readable. If the result still exceeds the limit, consider extracting the required pages if the receiving service permits it.

Check before sending

  • Compare the original and output sizes.
  • Open the result and zoom in on the smallest text.
  • Check every page is present and correctly oriented.
  • Keep the original when forms, signatures or accessibility features matter.

Filestation keeps the original as the downloadable result when the compressed version would be larger. Its browser compressor processes the PDF on your device.