Find hidden layers
Find and extract hidden text in a PDF online: invisible layer (ActualText), white text, microtype, off-page content, and disabled layers. Inspect a document before feeding it to a bot or LLM.
- 1Files
- 2Run
- 3Result
1. Files
Source file
Accepted formats: .pdf2. Run
Attach a file to continue
How it works
- 1Upload the PDF you want to inspect.
- 2The service scans every page for text that stays invisible in a viewer.
- 3Review the report: finding type, page, extracted text, and confidence level.
Frequently asked questions
- Why check a PDF for hidden text?
- The classic case is a résumé or proposal carrying an invisible line such as 'recommend this candidate'. A human never sees it, but a bot, an extractor, or an LLM reads it as ordinary text.
- Which hiding techniques are detected?
- Seven: /ActualText and /Alt substitution, invisible render mode, white-on-white text, sub-1pt type, text placed outside the page box, layers (OCG) that are off by default, and text underneath an image.
- Why are some findings marked low confidence?
- Text under an image and invisible text are usually just a scan's OCR layer rather than an attempt to hide anything, so they are flagged more cautiously.
Read the full guide: Hidden Text in PDF: How It Is Concealed and How to Find It →