You added annotations and signatures to a PDF. Now you're sending it as a final document — you don't want the recipient to be able to delete the signature or edit your comments out.
Flattening converts annotations to page content. They become permanent. Flint does it.
What flattening does
PDF stores annotations (highlights, comments, signatures) as separate objects layered on top of the page. Anyone with PDF tools can move or delete them. Flattening merges the annotations into the page's raster content — they become part of the page itself, not removable annotations.
When to flatten
Final documents that shouldn't be edited. Signed contracts (so the signature can't be removed). Reports that include reviewer annotations as part of the official record. Forms after they've been filled — flatten to prevent further form input.
When NOT to flatten
Documents still under review. Drafts. Anything where you (or the recipient) might want to remove or modify annotations later. Once flattened, the original annotation objects are gone — only the visual result remains.
Flattening in Flint
Open edit PDF, choose 'flatten'. Select what to flatten: annotations only, form fields only, everything. Apply. The output file has the flattened content baked in. Open in any reader — your signature is now part of the page, not a removable layer.
FAQ
Can I unflatten?
No. Flattening is permanent. Keep an unflattened original if you might need to edit later.
Does flattening affect text selection?
Flattened text is still selectable if the underlying text remained. Flattened form fields become rendered text (selectable if the renderer kept it as text).
Does flattening change file size?
Often slightly smaller — annotation overhead removed. Pure raster flattening (uncommon) increases size.
Will the recipient know it's flattened?
Only if they try to interact with annotations and discover they can't. Otherwise indistinguishable from a normal PDF.
Lock it down before sending. Flatten PDF pages.