Scanning and text recognition (OCR): Turning paper into digital documents

In short: With a scanner or phone camera, paper documents can be digitised; OCR recognises the text in them so that it becomes searchable and copyable.

In more detail: Stacks of paper can be filed well as PDF. A scan is at first only an image. Only optical character recognition (OCR) reads the writing and places a searchable text layer beneath it.

In Depth

Scanning

• Flatbed scanner or multifunction printer for good quality, sheet-fed scanner (ADF) for stacks.
• Phone apps (for example Microsoft Lens, Adobe Scan, Apple Notes “Scan Documents”, Google Drive) correct perspective and contrast automatically.
• Resolution: 200 to 300 dpi suffice for documents, 600 dpi for small type or photos.
• Colour only when needed; greyscale or B/W save space.

OCR

Programs: Adobe Acrobat, ABBYY FineReader, free Tesseract (open source, tesseract image.png output -l eng), OCRmyPDF (makes PDFs searchable), phone apps and cloud services. Quality depends on a clean scan, a straight sheet, contrast and the right language. Handwriting and poor originals are often recognised wrongly, so check the result.

Filing and order

Name files consistently (2026-05-12_Invoice_Telecom.pdf), sort into folders (tax, insurance, contracts, warranty) and use a document archive such as Paperless-ngx. Mind retention periods (for example invoices for a business 8 to 10 years, warranty receipts until expiry). Still keep originals of important documents (birth certificate, signed contracts).

Privacy

Documents often contain sensitive data (ID, proof of income). Use apps from trustworthy providers, enable cloud upload only deliberately, encrypt the archive and secure it with backup. Delete scans of IDs when no longer needed.

See also: Creating and reading PDF files, Backup strategy, Homelab and self-hosting, Barcode scanners