What is UFO?

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

What is AFM?

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

When Should You Use UFO vs AFM?

UFO vs AFM: Key Differences

• •UFO and AFM 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.
• •Alpha channel support: AFM lacks transparency support.
• •UFO files are typically 100KB to 10MB+ depending on glyph count while AFM files range Very small, text-based metrics
• •Primary audience: UFO is built for font design and editing, collaborative font development, glyphs/robofont scenarios, while AFM focuses on postscript font metrics, pdf font embedding — pick the format that matches your output requirement.

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.

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.

Common Use Cases for UFO to AFM Conversion

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

Industry Applications

Best Practices for UFO to AFM Conversion

• →Converting UFO to AFM: check that glyph coverage is preserved — some formats have character limitations
• →Use AFM for websites where file size matters
• →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 UFO to AFM Conversion

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

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