How to improve PDF scan quality

1 min read·25 July 2026

A poor quality PDF can be hard to read, large in size, and not searchable. Here you learn how to improve quality — from scan settings to compression and OCR.

Scan at the right resolution

Scan at a minimum of 300 dpi for readable documents. For archiving choose 600 dpi. Higher resolutions produce larger files without a clearly visible benefit. Save as PDF or TIFF for the best quality.

Straight and clean scan

Place the document flat on the scanner without creases. A crooked scan makes OCR recognition difficult. Some scanners have automatic straightening; otherwise rotate the pages after scanning using the rotation tool in PDFrust.

Compress PDF

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Compress without quality loss

After scanning at high resolution the file size is large. Compress via PDFrust at the high quality level: file size drops significantly while text stays sharp.

OCR for searchability

A scanned PDF is an image: you cannot search anything in it. Use the OCR tool in PDFrust to recognise the text and make it searchable. Choose the correct language for the best results.