A PDF arrives by email. Opening it reveals what looks like a printed document. The text is there, the formatting is correct. But can you select the text with the cursor, or does the cursor pass over it as if it were a photograph? The answer determines whether the PDF was created by scanning paper or generated from a digital source, and it determines everything about how you can work with the file.
Clicking on text and watching whether the cursor selects it or ignores it answers the question in one second.
Determining whether a PDF was scanned or created digitally involves checking for selectable text, examining the file structure, and looking for tell-tale visual artifacts of scanning. WukongPDF's OCR PDF tools can make scanned documents searchable, and the Scanned PDF identification steps below tell you whether you need OCR in the first place.
The Text Selection Test
Open the PDF and try to select a word of text with the text selection tool. If the cursor highlights the word character by character, the PDF contains selectable text and was created digitally or has already been OCR'd. If the cursor draws a selection rectangle over the entire area without highlighting individual characters, the page is an image and the PDF was created by scanning.
The text selection test is fast and definitive for single-page checks. For multi-page documents, test a few pages from the beginning, middle, and end. Some PDFs mix digital and scanned pages, typically a digitally created cover letter followed by scanned attachments. The text selection test on each page reveals which pages are which.
Checking File Size and Page Count for Clues
Scanned PDFs are typically larger than digital PDFs with the same page count because each page is a full-page image. A 10-page scanned PDF at 300 DPI is often 5-15 MB. A 10-page digital PDF of the same content might be 100-500 KB. The file size difference is a quick clue before even opening the file.
Scanned PDFs also tend to have fewer internal features. No bookmarks, no hyperlinks, no embedded fonts, no metadata beyond basic file properties. Open Document Properties and check the Fonts tab. A scanned PDF has no fonts listed because all content is images. A digital PDF lists the fonts used in the document.
Checking the File Properties for Creation Method
Document Properties often include the application that created the PDF. A PDF created by Adobe Acrobat from Microsoft Word was likely digital. A PDF created by Canon Scanner Driver or HP Scan was scanned. A PDF created by an OCR application may be a scanned document that has been processed for searchability.
The producer field in Document Properties is set by the creating application and is not always reliable because it can be changed or spoofed. Combine the producer information with the text selection test and the font check for a confident determination. Three independent tests pointing to the same conclusion are reliable.
| Test | Digital PDF Result | Scanned PDF Result |
|---|---|---|
| Text selection | Cursor highlights individual characters | Cursor draws selection rectangle over image |
| File size (10 pages) | 100-500 KB | 5-15 MB |
| Fonts tab in Properties | Lists embedded fonts | Empty, no fonts |
| Producer field | Word, Acrobat, Chrome | Scanner driver, imaging software |
Looking for Visual Artifacts of Scanning
Zoom in to 400% on a text area. Scanned PDFs show the characteristic artifacts of image capture: slight blur at character edges, uneven darkness across the page from scanner lighting, and dust specks or hair marks on the scanner glass that appear as faint lines or spots. Digital PDFs show crisp character edges at any zoom level.
Scanned PDFs of double-sided pages may show ghosting, faint reversed text from the other side of the paper bleeding through. This is a definitive sign of scanning because digital PDFs have no concept of paper opacity. Ghosting appears as a gray shadow of text behind the primary text, most visible in areas where the primary text is sparse.
Using PDF Metadata Fields for Additional Clues
The PDF metadata fields, accessible through Document Properties, can reveal the document's origin. A Title field containing the original document filename, like Annual-Report-2025-Final.docx, indicates the PDF was created from that Word file. An empty Title field or a Title that matches the PDF filename is neutral. A Creator field listing Microsoft Word or Google Docs indicates digital origin.
The Creation Date and Modification Date fields can provide timeline clues. A PDF created and modified on the same date within minutes of each other suggests a direct digital export. A PDF with a modification date years after the creation date may have been OCR'd or processed. The metadata tells the document's history, and that history reveals whether scanning was involved.
What to Do Once You Know the PDF Type
For scanned PDFs that need to be searchable, run OCR to add a text layer. The OCR process recognizes the text in the page images and adds selectable, searchable text behind them. The visual appearance does not change. The PDF gains searchability and copy-paste capability.
For digital PDFs that need to look scanned, typically for official-looking document reproductions, conversion to image and back is unnecessary and degrades quality. The digital PDF is already in its optimal form. Any processing that converts text to images reduces quality without adding value.