Convert Mac Font Suitcases with FontForge

FontForge is capable of converting legacy Macintosh font suitcase files into modern, cross-platform formats such as OpenType (OTF) and TrueType (TTF). Although the software natively supports these vintage formats, a successful conversion depends on preserving the classic Mac OS resource fork and having all accompanying outline files on hand. This article explains how FontForge processes Mac font suitcases, what prerequisite files are required, and the steps to convert them for modern operating systems.

Understanding the Mac Suitcase Format

Classic Mac OS stored font information in the file's "resource fork" rather than the standard "data fork" used by modern operating systems. Font suitcases typically fall into two categories:

  • TrueType Suitcases: These contain complete font data, including scalable glyph outlines and bitmap strikes, embedded entirely within the suitcase.
  • PostScript Type 1 Suitcases: These contain only the screen fonts (bitmaps and metric data like kerning). The scalable vector outlines reside in separate printer font files (often named using a shortened six-letter convention, known as LWFN files).

The Resource Fork Challenge

Modern operating systems, particularly Windows and standard Linux distributions, do not natively recognize Mac resource forks. If a suitcase is transferred via email, flash drives, or non-Mac file systems without archiving, the resource fork may be stripped, leaving a zero-byte or unreadable file.

To open a suitcase in FontForge, the resource fork must be intact. FontForge handles resource data when packaged in the following ways:

  • Native resource forks on macOS.
  • MacBinary files (.bin).
  • BinHex files (.hqx).
  • AppleDouble files (the hidden ._ files created when Mac files are placed on non-HFS file systems).
  • Modern Mac Data Fork Suitcases (.dfont).

Converting TrueType Suitcases

Converting a TrueType suitcase is straightforward because the file contains all necessary vector data:

  1. Open FontForge and choose File > Open.
  2. Navigate to the suitcase file. If the resource fork is intact, FontForge will display a sub-dialog listing all font weights and styles contained within the suitcase.
  3. Select the font face you wish to extract and click OK.
  4. Review the glyphs in the main editing window.
  5. Choose File > Generate Fonts, select OpenType (CFF) or TrueType, and click Generate to save the new font.

Converting PostScript Type 1 Suitcases

For PostScript Type 1 fonts, FontForge requires both the suitcase (containing the FOND resource) and the external outline files:

  1. Place the suitcase file and all corresponding printer outline files in the exact same directory.
  2. In FontForge, navigate to and open the suitcase file.
  3. FontForge will automatically scan the folder for the corresponding PostScript outline files to reconstruct the vector glyphs.
  4. If an outline file is missing, FontForge will only load bitmap representations, which cannot generate a scalable modern font.
  5. Once loaded, choose File > Generate Fonts to export the font as an OpenType (CFF) or TrueType file.

Post-Conversion Checks

Legacy fonts frequently utilize obsolete character encodings (such as Mac OS Roman) instead of Unicode. After importing a suitcase, check Encoding > Reencode > ISO 10646-1 (Unicode, BMP) in FontForge to verify that characters are correctly mapped to their modern Unicode positions before exporting.