T42 to PPM Converter

T42 (Type 42) is a PostScript font format developed by Adobe Systems that wraps a TrueType font inside a PostScript font dictionary, enabling PostScript printers equipped with a TrueType rasterizer to print TrueType fonts natively. The name reportedly references Douglas Adams' "The Hitchhiker's Guide to the Galaxy," where 42 is the answer to the ultimate question. Type 42 was introduced with PostScript interpreter version 2013 in the mid-1990s, with Adobe publishing the formal specification as Technical Note #5012 in July 1998. The format embeds the complete TrueType font data — outlines, hinting instructions, and tables — as a binary string within the PostScript sfnts dictionary entry, while wrapping it in standard PostScript font structure including CharStrings, Encoding, and FontInfo dictionaries. One advantage is preserved TrueType hinting: because the original quadratic spline outlines and grid-fitting instructions are passed directly to the TrueType rasterizer, the printed output matches the screen rendering quality that TrueType hinting was designed to deliver. This is superior to the alternative approach of converting TrueType outlines to Type 1 cubics, which discards hinting. Type 42 also enables PostScript workflows to incorporate the vast library of TrueType fonts bundled with Windows and macOS without manual font conversion. PDF generators commonly use Type 42 embedding when including TrueType fonts in PostScript-based output pipelines. The format bridges two major font technologies that evolved separately, ensuring interoperability across the PostScript and TrueType ecosystems.