CID Converter

CID (Character Identifier) is a font architecture developed by Adobe Systems and specified in June 1993 to address the challenges of fonts containing very large glyph sets, particularly for CJK (Chinese, Japanese, Korean) scripts. Traditional PostScript fonts identify glyphs by name, which becomes impractical when a font contains tens of thousands of characters — a typical Japanese font may include over 20,000 glyphs. CID-keyed fonts replace glyph names with numeric identifiers organized by a character collection and ordering (such as Adobe-Japan1 or Adobe-GB1), dramatically reducing overhead for glyph access and subsetting. The architecture defines three PostScript font types: Type 9 (CID-keyed Type 1 outlines), Type 10 (CID-keyed Type 3), and Type 11 (CID-keyed Type 42/TrueType). A primary advantage is efficient handling of massive character sets — the numeric CID approach eliminates the memory and processing cost of maintaining thousands of glyph name strings. CID fonts also support sophisticated CMap resources that map encoding values to CIDs, enabling a single font to serve multiple encoding schemes (Unicode, Shift-JIS, Big5) without duplicating glyph data. The architecture integrates well with PDF subsetting, allowing documents to embed only the glyphs actually used. CID-keyed technology laid the foundation for CJK support in both OpenType and modern PDF workflows, and remains active in print production and document processing systems worldwide.