PT3 to PBM Converter

PT3 (PostScript Type 3) is a font format defined as part of the PostScript language specification, introduced by Adobe Systems in 1984. Unlike Type 1 fonts, which use a restricted subset of PostScript operators optimized for hinting and efficient rendering, Type 3 fonts allow the full PostScript language to describe each glyph. This means glyphs can incorporate graduated fills, grayscale shading, complex path operations, color, and even bitmap images — capabilities impossible within Type 1's constrained charstring interpreter. Adobe originally kept the Type 1 specification secret and proprietary, so third-party type foundries and developers who wanted to create PostScript-compatible fonts had to use the publicly documented Type 3 format during the late 1980s. A notable advantage is creative freedom: because any valid PostScript program can define a glyph, designers can produce decorative, illustrated, and textured letterforms that go far beyond simple outline fills. The format's openness was another practical strength in its era, enabling anyone to create PostScript fonts without licensing Adobe's proprietary hinting technology. However, Type 3 fonts lack the hinting mechanisms that make Type 1 text crisp at small sizes and low resolutions, which limited their use for body text. When Adobe published the Type 1 specification in March 1990, most foundries migrated to the hinted format. Type 3 fonts remain primarily of historical interest, encountered in archived PostScript documents and specialized applications where artistic glyph rendering outweighs the need for screen-optimized hinting.