What is AFM?

Adobe Font Metrics (AFM) is a text file describing Type 1 font metrics including character widths, kerning pairs, and bounding boxes.

What is UFO?

UFO (Unified Font Object) is an open, XML-based font source format used by professional font editors for collaborative font development.

When Should You Use AFM vs UFO?

AFM vs UFO: Key Differences

• •The core technical difference: AFM relies on lossless compression whereas UFO uses lossless compression.
• •Neither format changes compression philosophy — both are lossless compression — so any size differences are due to encoding efficiency, not a shift in quality approach.
• •Transparency: N/A
• •File sizes: AFM files typically range Very small, text-based metrics and UFO files 100KB to 10MB+ depending on glyph count.
• •Primary audience: AFM is built for postscript font metrics, pdf font embedding scenarios, while UFO focuses on font design and editing, collaborative font development, glyphs/robofont — pick the format that matches your output requirement.

Advantages of AFM

• ✓AFM applies lossless compression specifically calibrated for PostScript font metrics, PDF font embedding.
• ✓AFM enjoys broad native support across operating systems, browsers, and creative tools alike.
• ✓AFM guarantees every bit of the original data survives — no approximations, no shortcuts.
• ✓You will find AFM support built into virtually every tool that handles PostScript font metrics, PDF font embedding — no plugins or converters needed.

Advantages of UFO

• ✓The lossless nature of UFO means file sizes stay reasonable while handling Font design and editing, collaborative font development, Glyphs/RoboFont efficiently.
• ✓From mobile devices to enterprise servers, UFO is recognized and supported everywhere.
• ✓The trade-off for UFO's perfection is larger files — but for archival work, it is worth every megabyte.
• ✓UFO is a first-class citizen in all major software ecosystems, from creative suites to development environments.

Common Use Cases for AFM to UFO Conversion

• Marketing materials
• Packaging design
• Signage systems
• Icon sets
• Logo design
• Data visualization

Industry Applications

Best Practices for AFM to UFO Conversion

• →Converting AFM to UFO: check that glyph coverage is preserved — some formats have character limitations
• →Use UFO 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 AFM to UFO Conversion

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

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