BASALT · JOURNAL
When PDF fonts look wrong on another machine
A PDF that renders correctly for you and badly for the recipient almost always has a font embedding problem.
What embedding means
A PDF can either include the font it uses or merely reference it by name. If the font is embedded, the document renders identically everywhere. If it is referenced, the viewer substitutes something it has, and layout shifts.
Documents made on a machine with the font installed look right on that machine regardless, which is why the author is the last person to notice.
Checking
pdffonts document.pdfThe output lists each font with an emb column. Anything showing no will be substituted on a machine without that font.
Fixing it
Re-export from the source document with font embedding enabled, which is a setting in most applications and is often off by default for licensing reasons.
If you no longer have the source, the practical options are to accept substitution or to render the pages to images, which fixes appearance permanently at the cost of searchability.
Subset fonts and a related problem
Many PDFs embed only the characters used, which is sensible and keeps files small. A side effect is that subset fonts sometimes lack a mapping back to Unicode, so the document renders perfectly and copies as gibberish.
That is worth knowing for a specific reason: it makes copy and paste unreliable as a test of whether text was removed from a document. A file can hold the original text and paste nothing legible.
For anything being filed
Court and regulatory filing systems frequently require all fonts embedded, and reject filings that fail the check. pdffonts answers the question in a second and is worth running before submitting rather than after being rejected.
Frequently asked questions
Why do PDF fonts look different on another computer?
Because the fonts were referenced rather than embedded, so the recipient's viewer substitutes something it has. Documents look correct on the machine that has the font installed, which is why the author rarely notices.
How do I check whether PDF fonts are embedded?
Run pdffonts document.pdf and read the emb column. Any font showing no will be substituted on a machine that does not have it.
How do I fix missing font embedding?
Re-export from the source document with embedding enabled, which is often off by default. Without the source, the options are to accept substitution or render pages to images, which fixes appearance at the cost of searchability.
What is a subset font?
A font where only the characters actually used are embedded, which keeps files small. Some subsets lack a mapping back to Unicode, so the page renders correctly while copied text comes out as gibberish.
Doing it in Basalt
Basalt is a native macOS PDF toolkit: eighteen tools in one window covering merge, split, page organisation, compression, OCR, passwords, Bates numbering, forms, signing, watermarks and comparison. Every file is processed on your Mac, and the engine that opens documents holds no network entitlement at all, which macOS enforces at the code-signature level. Redaction destroys content rather than covering it, and an independent verifier proves the material is gone before a file is written. A one time $29 licence covers up to three Macs, free for the first 24 hours. basaltformac.com, or brew install --cask chipmunk1101/tap/basalt.
Redaction that proves itself
Basalt destroys the content you mark, then re-opens the file it wrote and proves the content is gone before it saves anything. Your documents never leave your Mac.