OCR for PDFs and Images: How to Get Accurate Text

Optical character recognition reads the shapes of letters in an image or a scanned page and turns them into real, selectable text.

What OCR Actually Does

A scanned page, or a photo of a document, is just an image, a grid of pixels with no notion of letters or words. OCR analyzes that grid, recognizes character shapes, and outputs the text it finds along with the position of each recognized word on the page.

Searchable PDF vs Extracted Text

OCR PDF adds an invisible, searchable text layer over the original page image, so the page still looks exactly like the scan but the text underneath is selectable and searchable in any PDF viewer. Image to Text instead extracts the recognized text on its own, with no page image involved, for when you just want the words.

Languages and Auto-Detection

Recognition supports 95 or more languages. Language can be auto-detected page by page, which is convenient for mixed documents, or you can pick one or more languages manually when you know exactly what the document contains. Manual selection tends to be more accurate than auto-detection for short or unusual documents where there is not enough text to detect language reliably.

Scan Quality Tips

Pages are read at 300 dpi, which is a good baseline for standard printed text. A few habits make a real difference to accuracy:

• Keep the page straight; skewed text reduces recognition accuracy noticeably.
• Use even lighting and avoid shadows across the page, since low contrast confuses character shapes.
• Scan at 300 dpi or higher rather than relying on a low-resolution phone photo.
• Flatten curled or folded pages before scanning where possible.

Mixed-Language Documents

For a page that switches between two or three languages, select all the relevant languages manually rather than relying on auto-detection, which works per page and may miss a language that only appears in a small section of that page.

Tables and Forms

OCR recognizes the text inside table cells and form fields, but it does not always preserve the original grid structure perfectly, especially with thin borders or unusual layouts. Check numeric tables carefully, since a misread digit is easy to miss visually.

Handwriting Limits

Recognition accuracy drops sharply on handwriting, and it drops further with small print, decorative fonts, low contrast and skewed pages. Neat, printed block letters fare better than cursive handwriting, but no OCR tool here is a reliable replacement for a human transcription of handwritten notes.

Checking Results

Always spot-check OCR output against the original, particularly numbers, names and any text in small print. A quick skim of a converted page catches most recognition errors before they cause a downstream problem.

Choosing the Right Tool

Use OCR PDF when the final file needs to keep looking like the original scan but become searchable. Use Image to Text when you only need the recognized words, with no page image. Use Scan to Markdown when the scanned document has structure, headings, lists or tables, worth preserving as Markdown, as covered in the PDF to Markdown guide. Use PDF to Word when the end goal is an editable document rather than plain text. Whichever tool you pick, a quick manual review of the first page against the output remains the fastest way to confirm the settings you chose were the right ones for that particular document.