What do the fsType values mean?

fsType Name What it allows
0 Installable Embedding, and installing the font on the reader’s computer.
2 Restricted License Nothing without the owner’s permission.
4 Preview & Print Embedding for viewing and printing; no edits may be applied to the document.
8 Editable Embedding, with editing allowed and saved.

Two more bits can be added: 256 forbids subsetting, and 512 allows embedding bitmaps only. As the OpenType specification puts it, “Embedding licensing rights are granted by the vendor of the font.”

How do you check a font’s embedding permissions?

On Windows, open the Fonts control panel and select the font. Microsoft’s support article then says: “At the bottom of the window, check the details about the font. One of the details is named Font embeddability”.

On a Mac, read the field from the font file. We used the open-source opentype.js library in Node.js:

import opentype from 'opentype.js';
for (const file of process.argv.slice(2)) {
  console.log(file.split('/').pop(), opentype.loadSync(file).tables.os2.fsType);
}

For IBM Plex Serif and for Georgia as macOS installs it, it prints:

IBMPlexSerif-Regular.ttf 0
Georgia.ttf 8

The demo documents made for PDF Textfix use IBM Plex, whose SIL Open Font License says the fonts “can be bundled, embedded, redistributed and/or sold with any software”; all five of IBM’s files read 0.

In a PDF, the flags survive only when the producer kept the font’s OS/2 table. pdffonts shows that the demo letter embeds subsets, but not the flags:

name                                 type              encoding         emb sub uni object ID
------------------------------------ ----------------- ---------------- --- --- --- ---------
AAAAAB+IBMPlexSerif-SemiBold         TrueType          MacRoman         yes yes no       8  0
AAAAAC+IBMPlexSerif-Regular          TrueType          MacRoman         yes yes no       9  0

How this was tested, on October 12, 2026

None of the 15 TrueType subsets that macOS embedded in the six demo documents has an OS/2 table, so none carries flags. On macOS 27.0.1, on October 12, 2026, the system fonts gave 4 for Avenir, Avenir Next and Palatino, 8 for Georgia, Arial and Times New Roman, and 0 for Baskerville, Didot and Optima.

Can you edit a PDF that uses a restricted font?

The specification says what the flags allow for the font: whether it may be embedded and, for Preview & Print, that “no edits may be applied to the document” that carries it. Whether your licence lets you edit a document set in such a font is a question for that licence, and the terms leave it with you.

What PDF Textfix does with such a font: it never extends the font, never borrows another subset of the same face from the file and never embeds the face again from an installed copy. An edit of a line set in a Restricted or Preview & Print font reuses the glyphs and codes the file already holds for that font. A missing character comes from another font when one fits; otherwise the edit is refused, with the licence as the reason. The line carries a licence badge, and the Issues pane (⌥⌘I) names the font.

For fonts installed on your Mac, PDF Textfix refuses to embed one marked Restricted License or bitmap-only, and says “The licence of the installed font that draws this character does not allow embedding it.”

An installed font marked Preview & Print or Editable can be embedded to draw a missing character; for the first, the line’s badge adds the words preview and print only. Whether the font’s licence allows that use is yours to check, as the terms say.

What if a font’s licence blocks your edit?

The flags are the maker’s statement; the licence is the contract. When a restricted font blocks a character, use one the line already has, or export the PDF again with a font licensed for editing. Font not embedded in PDF covers the opposite case.

Questions about embedding permissions

How do you change a font's embedding permissions?

Only with the owner’s permission. A font editor can rewrite the field, but not the licence, and apps that embed a font “must not modify the embedding permissions and restrictions indicated in this field”.

What does fsType 0 mean?

Installable embedding, the least restrictive value.

Can every embedded font be edited?

Not by the font maker’s terms: a Preview & Print font allows embedding for viewing and printing only. PDF Textfix still edits lines in such a font with the characters the file already holds, never builds a new font from it, and marks the line with a licence badge.