What does Flatten to Image PDF change?
It renders every page to a pixel image using PDF.js, then embeds those images in a new PDF. The original PDF structure is completely destroyed: fonts, forms, annotations, JavaScript, layers, EXIF, and metadata are all gone. What remains is exactly what you see on screen — nothing more.
What this does not protect
- Text becomes non-selectable. Recipients cannot copy-paste, search, or index the text. If they need searchable text, they would need to OCR the result.
- Output file size is almost always larger than the original for text-heavy documents. A 500KB text PDF may become 3-5MB after flatten at 150 DPI.
- 200-page cap exists because each page requires ~50-100MB of RAM for canvas rendering. For longer documents, split first and flatten sections.
- Transparent elements and blend modes may render differently than in specialized PDF viewers. Always verify the output.
- It cannot fix compromised devices, accounts, or unsafe sharing channels.