What is OTC?

OpenType Collection (OTC) bundles multiple OpenType fonts into one file, similar to TTC but for OpenType format.

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 OTC vs AFM?

OTC vs AFM: Key Differences

• •OTC 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.
• •How transparency is handled: AFM supports transparency, so alpha information is preserved during conversion.
• •Storage footprint: 5-30MB for font collections for OTC vs Very small, text-based metrics for AFM.
• •Use case fit: OTC targets font distribution, font family packaging and AFM targets postscript font metrics, pdf font embedding — your choice depends on which workflow stage you are serving.

Advantages of OTC

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

Advantages of AFM

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

Common Use Cases for OTC to AFM Conversion

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

Industry Applications

Best Practices for OTC to AFM Conversion

• →Converting OTC 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 OTC 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 OTC → 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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