Type 1, TrueType, and OpenType Fonts in PDF: What's the Difference?
PDFs can embed Type 1, TrueType, and OpenType fonts. Learn how they differ technically, which is best for print and screen, and why it matters for PDF compatibility.
PDFs can embed three main font technologies: Type 1 (the original PostScript format), TrueType (developed by Apple and Microsoft), and OpenType (the modern unified standard). Each stores glyph outlines differently and has different capabilities for international character support, hinting quality, and compatibility. Understanding the differences matters for print production, archiving, and long-term compatibility.
Type 1 Fonts
Type 1 (also called PostScript Type 1) was the dominant professional font format from the late 1980s through the 2000s. Glyph outlines are described using cubic Bézier curves in PostScript language. Type 1 fonts support only 256 glyphs per font file (extended Latin, no multi-byte encoding) — for extended character sets, multiple font files were needed. Type 1 fonts have high-quality printer hinting, making them still excellent for print output. Adobe officially discontinued Type 1 support in 2023 — newer versions of Adobe software no longer support creating Type 1 fonts, though existing embedded Type 1 fonts in PDFs remain valid.
TrueType Fonts
TrueType was developed jointly by Apple and Microsoft as a scalable font format that could be controlled entirely by the OS without licensing Adobe's Type 1 technology. TrueType uses quadratic Bézier curves (simpler than cubic), supports large character sets (up to 65,535 glyphs per font), and uses a bytecode hinting system that gives fine control over rendering at small sizes on screen. Windows system fonts (Arial, Times New Roman, Calibri) are TrueType. When embedded in PDFs, TrueType works well but can be slightly larger than equivalent CFF/Type 1 outlines due to quadratic vs cubic representation.
OpenType Fonts
OpenType is the current standard, developed jointly by Adobe and Microsoft. It's a container format that can hold either TrueType outlines (OpenType with TrueType outlines = OTF/TTF) or CFF outlines (OpenType with PostScript outlines = OTF with CFF). OpenType adds: Unicode encoding supporting millions of characters, advanced layout features (ligatures, small caps, alternate glyphs, contextual substitution), and a single file supporting both Mac and Windows. Most Google Fonts and modern commercial fonts are OpenType. When embedded in PDF, OpenType fonts provide the best combination of quality, feature support, and compact file size.
CID Fonts for CJK
For Chinese, Japanese, and Korean text, PDFs use CID-keyed fonts (a variant of Type 1 and CFF technology) because these scripts require tens of thousands of glyphs — far beyond what a standard Type 1 font supports. CID fonts use a two-byte character identifier rather than a single byte, enabling large character repertoires. CID-keyed OpenType fonts with CJK character sets can be 10-20 MB unsubsetted, making font subsetting critical for CJK PDFs.
Which Font Format Is Best for PDF?
For professional print production: OpenType with CFF outlines (PostScript flavored) for its compact size and excellent hinting. For screen-optimized PDFs: TrueType or OpenType with TrueType outlines for better screen rendering hints. For long-term archival (PDF/A): any format that can be fully embedded and includes a ToUnicode mapping — most modern OpenType fonts qualify. Avoid relying on Type 1 for new documents given the end of Adobe support.
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