PDF editing guides
What a PDF actually contains, why editing one is harder than it looks, and what this editor does about it. Written from the rules the software really applies, not from a general description of the format.
Something went wrong
- The text will not edit
Five reasons a PDF's text cannot be changed, and how to tell which one you have.
- The font changed
Why an edit can come back in a different face, and which faces are substituted.
- Copied text is garbled
What a missing character map is, and why an editor has to refuse rather than guess.
- An edit left a patch
Why covering old text can show, and when nothing has to be covered at all.
How it works
- Text-based vs scanned PDFs
The difference, how this service decides which you have, and what it will not do.
- Font subsetting
What the six-letter prefix on a PDF font means and why it makes editing harder.
- How PDF text editing works
What a page really contains, and the rules this service uses to grade every block of text.
- Is the old text removed?
Sometimes — and never dependably enough to treat editing as redaction.
Ready to try it? Open the editor.