What is PFM?

Printer Font Metrics (PFM) is the binary companion to PFB fonts for Windows, containing font metric data for printing.

What is SFD?

Spline Font Database (SFD) is the native project file format for FontForge, an open-source font editor for font design.

When Should You Use PFM vs SFD?

PFM vs SFD: Key Differences

• •PFM and SFD diverge on compression: lossless compression for the source, lossless compression for the target.
• •Both formats share lossless compression, so quality behavior is similar across the two — file size differences come from algorithm efficiency rather than compression philosophy.
• •Transparency: N/A
• •Storage footprint: Very small, binary format for PFM vs Larger than production fonts due to editing metadata for SFD.
• •Use case fit: PFM targets windows postscript printing, font pairing and SFD targets font design and editing, fontforge projects — your choice depends on which workflow stage you are serving.

Advantages of PFM

• ✓PFM compresses data using lossless methods, keeping file sizes manageable for Windows PostScript printing, font pairing.
• ✓Industry-wide support means PFM files open anywhere — from legacy systems to the latest devices.
• ✓Lossless quality makes PFM the gold standard for archival and master copies.
• ✓From professional software to open-source alternatives, PFM works out of the box.

Advantages of SFD

• ✓At its core, SFD relies on lossless encoding — a design choice that makes it perfect for Font design and editing, FontForge projects.
• ✓You won't run into compatibility issues with SFD — it's a universal standard across platforms.
• ✓File size management with SFD: larger files guaranteed to match the original exactly.
• ✓Every major application in the Font design and editing, FontForge projects space supports SFD natively.

Common Use Cases for PFM to SFD Conversion

• E-book formatting
• User interfaces
• Marketing materials
• Packaging design
• Signage systems
• Icon sets

Industry Applications

Best Practices for PFM to SFD Conversion

• →Converting PFM to SFD: check that glyph coverage is preserved — some formats have character limitations
• →Use SFD for cross-platform compatibility
• →Test fonts across different browsers and operating systems after conversion
• →Always keep a backup of your original files before converting
• →Choose the appropriate quality settings for your specific use case

Troubleshooting PFM to SFD Conversion

• !The converted SFD font has incorrect metrics → advance width and kerning values may differ between formats despite identical glyphs
• !SFD file looks heavier or lighter than PFM → font rendering engines handle weight and anti-aliasing differently per format
• !OpenType features (ligatures, swashes) lost after conversion to SFD → verify the target format supports advanced typographic features
• !Variable font axes missing from the converted SFD → variable font support varies significantly between formats

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