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Scanned PDFs, image PDFs and OCR explained

A PDF can contain real text, pictures of text or a combination of both. That determines which edits are practical.

Know what type of PDF you have

Try selecting a word in your PDF viewer. If you cannot select text, it may be a photo-based scan. An image PDF stores visual pixels, while a text-based PDF stores drawing operations, character information and font references. This difference affects accessibility, searchability and editing.

Understand OCR

Optical character recognition analyses an image and attempts to identify letters and words. OCR can make text searchable, but its accuracy depends on image quality, language, skew, font and background. Always check numbers, names and special characters after OCR.

Create a PDF from photos

Using the Images to PDF utility, you can combine JPG and PNG files into a single document. Each photo becomes an A4 page. Choose sufficiently high-resolution scans and keep pages upright and well lit. The tool does not automatically recognise the text within those images.

Do not confuse visibility with editability

A text-looking PDF may still be difficult to edit reliably because of subset fonts and overlapping drawing instructions. For important documents, use the editable original when available. It is usually safer and cleaner than attempting to rebuild typesetting from PDF drawing commands.

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