Why the font changes when you edit a PDF

What is going on

A PDF is not a Word document. It doesn't keep a paragraph that can reflow. It keeps instructions to draw each letter, in a font, at a place on the page.

Most PDFs carry a copy of the fonts they use inside the file, so they look the same on every screen. To keep the file small, that copy often holds only the letters the document actually uses.

So when an editor needs a letter that isn't in that copy, or can't read the font at all, it has to use something else, often a plain font like Arial or Times. That is the lookalike you see: your new word sits in a different typeface from the words around it.

How to check before you send

• Zoom in on the edited word, next to its neighbours. Compare the shape of the letters, the weight and the spacing.
• Look at the numbers. A swapped font shows most in digits, because their widths and shapes differ from font to font.
• Check the font list. Most PDF readers list a file's fonts in the document properties. A font that wasn't there before is the stand-in.

What keeps the original font

• An editor that uses the font already inside the file and doesn't swap in a stand-in. This is what Redraft does, as far as it can.
• The real font file, when the letter you need isn't in the file's copy. No editor can draw that letter in that exact font from the file alone. Redraft uses the closest matching font it can find. When you are signed in, its Fonts panel marks any font it can't match exactly and lets you upload the real .ttf or .otf file.
• The original file. If you still have the Word, Pages or design file, fix it there and export again.

Fonts have licences. Only upload a font file you are allowed to use.

Where Redraft falls short

It doesn't promise a perfect match every time. A font that is missing a letter, or that can't be read, gets the closest match, and the result can differ a little from the original. Look at the page before you download, and zoom in on what you changed.

A scanned page has no font at all, because its words are a picture.

More guides

• Fix a typo in a PDF
• Make certificates from a spreadsheet
• Edit any PDF and keep the font
• Mail merge, but for PDFs