You signed the PDF. Saved it. Opened it. The signature isn't there. Or it's there in your editor but recipients say they can't see it.
What's actually going wrong
Placed off-page. Signature was dropped outside the visible page area. Wrong layer. Signature is in an annotation layer that some viewers don't render. Transparent or white colour. Signature is invisible against the page. Cryptographic only. Some signatures are 'invisible signatures' — they prove integrity without visual mark.
The quick fix
Use Flint's sign tool. Flint flattens signatures into the page as visible content — they appear in every viewer, every device.
Verify placement: drag the signature visibly onto the page, not in margin or off-page. Choose dark ink (black or blue) for visibility on white pages.
If that didn't work
If the signature was created as invisible (cryptographic only, no visual mark), there's nothing to see — it's intentionally invisible. Check the signing tool's options for visible signature mode.
For signatures placed in annotation layers, flatten the PDF to bake them into the page. Edit PDF in Flint and use save-as-flat.
Prevent it next time
Use signature tools that flatten by default. Choose dark colours. Verify the signature appears in a fresh viewer before declaring done.
FAQ
What's an invisible signature?
A cryptographic signature with no visual element. It proves the file wasn't modified but doesn't show a visible mark on the page. Some workflows use these; most users want visible signatures.
Why does my signature show in one viewer but not another?
Different viewers render annotation layers differently. Flatten the signature into the page (via Flint) so every viewer shows it.
Can I make my signature larger?
Yes — most signing tools support resize after placement. Drag handles to enlarge.
Why is my signature blue but appears black on print?
Greyscale printing converts colours to black. Either your printer is set to mono, or it doesn't have working colour cartridges. Check print settings.
Visible signatures every time: Sign with Flint which flattens for universal display.