PostScript Type 1 Font Format

PostScript Type 1 is a font format developed by Adobe Systems in 1985 as an integral component of the PostScript page description language. For nearly four decades, Type 1 fonts served as the professional standard for digital typography, powering the desktop publishing revolution and defining quality benchmarks for print production worldwide. The format uses cubic Bézier curves to define scalable, resolution-independent glyph outlines with mathematical precision.

The Type 1 Ecosystem

Unlike modern single-file formats, Type 1 fonts require multiple companion files:

• Outline Files: PFB (Printer Font Binary) for Windows or PFA (Printer Font ASCII) for Unix/Mac containing encrypted glyph data
• Metrics Files: PFM (Printer Font Metrics) for Windows or AFM (Adobe Font Metrics) for Mac/Unix with character width and kerning data
• Installation Files: INF files (Windows) for font installation information

Revolutionary Impact

Type 1 fonts transformed digital publishing in the 1980s and 1990s:

• Enabled the desktop publishing revolution with Apple LaserWriter (1985)
• Replaced expensive proprietary typesetting systems with affordable computers
• Provided resolution-independent typography that scaled perfectly to any output device
• Established professional print standards used for magazines, books, and corporate materials
• Created the foundation for Adobe's extensive professional font library
• Powered PostScript printers, imagesetters, and RIP (Raster Image Processor) workflows

Format Variants

Current Status (2025)

In January 2023, Adobe officially announced the end of support for PostScript Type 1 fonts after 38 years of service. This marks the format's transition to legacy status, with Adobe Creative Cloud applications, modern operating systems, and professional workflows discontinuing Type 1 compatibility. The industry has standardized on OpenType, which offers all of Type 1's capabilities plus extensive modern typographic features, Unicode support, and cross-platform compatibility.

The PostScript Type 1 font format's 38-year reign represents one of the most influential developments in digital typography. Its evolution from revolutionary technology to legacy format illustrates the challenges of proprietary standards, market competition, and technological succession.

Genesis: The PostScript Problem (1982-1984)

Before PostScript, digital typography faced fundamental limitations:

John Warnock and Charles Geschke developed PostScript at Xerox PARC as a device-independent page description language. Xerox's decision not to commercialize it led Warnock and Geschke to found Adobe Systems in December 1982, with PostScript as their flagship technology.

The LaserWriter Revolution (1984-1985)

Type 1 fonts emerged from Adobe's partnership with Apple Computer:

• 1984: Apple licensed PostScript for the LaserWriter project
• 1985 (March): Apple LaserWriter debuts at $6,995 with 35 built-in Type 1 fonts
• Key innovation: Cubic Bézier curves enabled mathematically precise, resolution-independent outlines
• Quality breakthrough: 300 DPI laser output rivaled expensive typesetting systems
• Desktop publishing born: Combined with Aldus PageMaker (July 1985), professionals could produce publication-quality documents on desktop computers

Professional Dominance (1985-1990)

Type 1 rapidly became the professional standard:

Adobe initially kept Type 1 specifications proprietary, licensing it to select partners. This exclusivity protected Adobe's business model but frustrated competitors and set the stage for Apple and Microsoft's TrueType challenge.

The TrueType Challenge (1991-1995)

Apple and Microsoft's joint TrueType development aimed to break Adobe's control:

In response to TrueType, Adobe published the Type 1 specification in 1990, democratizing high-quality font creation. However, Type 1 retained dominance in professional publishing while TrueType gained consumer market share.

Multiple Master Experiment (1991-1999)

Adobe's attempt to extend Type 1 with variable font technology:

• Concept: Single font file with interpolation axes (weight, width, optical size, etc.)
• Innovation: Conceptually similar to modern variable fonts, ahead of its time
• Challenges: Complex for designers, poor software support, limited adoption
• Discontinued 1999: Adobe abandoned MM fonts due to market failure
• Legacy: Influenced OpenType variable font specification (2016)

The OpenType Transition (1996-2010)

Adobe and Microsoft's collaborative OpenType format began Type 1's decline:

End of Life (2023)

Adobe's January 2023 announcement formally ended the Type 1 era:

Operating systems have also reduced support:

• macOS Catalina (2019): Warning dialogs for Type 1 fonts
• macOS Big Sur (2020): Type 1 installation difficult or impossible
• Windows 11: Limited Type 1 support, prioritizes OpenType
• Modern Linux: Requires legacy font rendering packages

Legacy and Lessons (2025+)

Type 1's 38-year journey offers important insights:

PostScript Type 1 fonts employ sophisticated yet constrained technical architecture designed for 1980s PostScript imaging model and computing environments.

Outline Technology

Type 1 defines glyph shapes using third-order (cubic) Bézier curves:

File Format Components

Encryption and Security

Type 1 fonts employ eexec encryption to protect outline data:

• Algorithm: Simple XOR cipher with fixed key (55665 decimal or 0xD971 hex)
• Purpose: Prevent casual copying and unauthorized modification
• Effectiveness: Not secure by modern standards; easily circumvented
• Legacy issues: Complicates font conversion, archiving, and analysis
• Modern view: Security through obscurity, primarily psychological deterrent

Character Encoding

Type 1's 256-glyph limitation necessitated complex encoding schemes:

Hinting System

Type 1 includes PostScript hints for low-resolution rendering:

• Stem hints: Maintain consistent vertical and horizontal stroke widths
• Alignment zones: Snap baseline, x-height, cap height, ascender/descender
• Blue values: Key vertical positions for alignment
• Flex hints: Handle curves near straight lines
• Ghost hints: Invisible hints for spacing control
• Limitation: Less sophisticated than TrueType's grid-fitting instructions

Font Dictionary Structure

Type 1 fonts are PostScript programs defining font properties:

Type 1 fonts are PostScript programs with defined structure and segments:

PFB File Segment Structure

Font Dictionary Example

%!PS-AdobeFont-1.0: MyFont-Regular 001.000
%%CreationDate: 1990:12:15 12:00:00
%%VMusage: 25000 35000
11 dict begin
/FontInfo 10 dict dup begin
  /version (001.000) readonly def
  /FullName (My Font Regular) readonly def
  /FamilyName (My Font) readonly def
  /Weight (Regular) readonly def
  /ItalicAngle 0 def
  /isFixedPitch false def
  /UnderlinePosition -100 def
  /UnderlineThickness 50 def
  /Notice (Copyright 1990 Adobe Systems) readonly def
end readonly def
/FontName /MyFont-Regular def
/PaintType 0 def
/FontType 1 def
/FontMatrix [0.001 0 0 0.001 0 0] readonly def
/Encoding StandardEncoding def
/FontBBox {-180 -250 1000 850} readonly def
/UniqueID 4567890 def
currentdict end
currentfile eexec
[binary encrypted data follows...]
[512 zeros for cleartext padding]
...encrypted CharStrings and Private dict...
cleartomark

AFM (Adobe Font Metrics) Structure

AFM files provide human-readable metrics in key-value format:

StartFontMetrics 4.1
Comment Generated by FontForge
FontName MyFont-Regular
FullName My Font Regular
FamilyName My Font
Weight Regular
ItalicAngle 0
IsFixedPitch false
UnderlinePosition -100
UnderlineThickness 50
Version 001.000
Notice Copyright 1990 Adobe Systems
EncodingScheme AdobeStandardEncoding
CapHeight 700
XHeight 450
Ascender 800
Descender -200
StdHW 76
StdVW 88

StartCharMetrics 256
C 32 ; WX 250 ; N space ; B 0 0 0 0 ;
C 33 ; WX 333 ; N exclam ; B 130 0 241 700 ;
C 65 ; WX 667 ; N A ; B 14 0 654 700 ;
C 66 ; WX 667 ; N B ; B 90 0 610 700 ;
...
EndCharMetrics

StartKernPairs 150
KPX A V -50
KPX A W -40
KPX A Y -55
KPX V A -50
...
EndKernPairs

StartComposites 12
CC Aacute 2 ; PCC A 0 0 ; PCC acute 200 180 ;
...
EndComposites

EndFontMetrics

CharString Format

Glyph outlines are defined using PostScript Type 1 CharString operators:

Typographic Features

Critical Limitations

• 256 glyphs maximum: Fundamental constraint requiring multiple fonts for comprehensive character sets
• No Unicode support: Platform-specific encodings (MacRoman, WinAnsi, etc.) created interoperability nightmares
• Multi-file dependency: Outline (PFB/PFA) + metrics (PFM/AFM) files must stay together
• Platform fragmentation: Different file formats and structures for Mac vs. Windows
• No OpenType layout: No GSUB/GPOS tables for advanced typography
• Weak encryption: eexec provides minimal protection, complicates archival
• Limited hinting: Less sophisticated than TrueType for low-resolution screens
• No web support: Never worked in browsers, no font embedding
• Complex installation: Manual file pairing and font management

Historical Usage (1985-2010)

Type 1 fonts dominated professional publishing and commercial printing:

• Book publishing: Industry standard for novels, textbooks, technical manuals
• Magazine production: Professional periodicals, catalogs, brochures
• Newspaper prepress: Daily and weekly publications (pre-PDF workflows)
• Commercial printing: High-end offset lithography and color separations
• Corporate branding: Identity materials, annual reports, presentations
• Advertising design: Print ads, packaging, point-of-sale materials
• Typesetting services: Professional typography shops and service bureaus
• PostScript RIP workflows: Imagesetters, platesetters, proofing systems

Legacy Persistence (2010-2023)

Type 1 remained in specific niche contexts:

• Document archives: Maintaining exact rendering of historical documents
• Print service bureaus: Supporting legacy customer files and reprints
• Specialized software: CAD applications, GIS systems, engineering tools
• Legacy RIP systems: Older PostScript imagesetters still in operation
• Font vendor libraries: Some foundries never converted entire catalogs
• Government documents: Agencies with strict format preservation requirements
• Educational institutions: Universities with legacy typesetting archives

Current Reality (2025)

Type 1 fonts have no place in active workflows:

• Adobe Creative Cloud: Photoshop, Illustrator, InDesign removed Type 1 support (2023)
• Operating systems: macOS Big Sur+ and Windows 11 provide limited or no support
• Web browsers: Never supported; use WOFF2 instead
• Mobile platforms: iOS and Android never supported Type 1
• Font vendors: All major foundries discontinued Type 1 distribution
• Modern RIPs: PDF workflows have replaced PostScript-native printing
• Conversion required: All Type 1 fonts must migrate to OpenType

Modern font formats offer comprehensive advantages over Type 1:

Type 1 to OpenType CFF Migration

OpenType with CFF (Compact Font Format) outlines is the direct successor to Type 1:

• Preserves outline quality: Cubic Bézier curves retained identically
• Single file format: No separate metrics files needed
• 65,536+ glyphs: Comprehensive character sets in one font
• Unicode encoding: Universal multilingual support
• OpenType features: GSUB/GPOS tables for advanced typography
• Cross-platform compatibility: Single font works on Mac, Windows, Linux
• Better hinting: PostScript hinting preserved plus TrueType options
• Web font support: Convert to WOFF2 for browser use

Converting Type 1 to OpenType

Professional conversion workflow for migrating Type 1 fonts:

# Single font conversion
fontforge -lang=ff -c '
  Open($1);
  Reencode("unicode");
  Generate($2);
' myfont.pfb myfont.otf

# Batch conversion script
#!/bin/bash
for pfb in *.pfb; do
  base=${pfb%.pfb}
  fontforge -lang=ff -c "
    Open(\"$pfb\");
    Reencode(\"unicode\");
    SetFontNames(\"$base\", \"$base\", \"$base\");
    Generate(\"$base.otf\");
  "
done

# Python script for advanced conversion
import fontforge
font = fontforge.open("myfont.pfb")
font.encoding = "unicode"
font.generate("myfont.otf", flags=("opentype",))
font.close()

Conversion Quality Checklist

• Verify outline integrity: Compare converted glyphs against original at multiple sizes
• Check metrics accuracy: Test character widths, sidebearings, and vertical metrics
• Validate kerning pairs: Ensure all kerning transferred correctly from AFM/PFM
• Test character encoding: Verify Unicode code point assignments
• Inspect hinting: Check if PostScript hints converted properly
• Review font metadata: Confirm name, version, copyright information
• Test in production: Verify converted fonts in actual documents and applications
• Document any issues: Note problems for troubleshooting or vendor contact
• Validate licensing: Ensure conversion rights and proper font licensing

Common Conversion Challenges

Legacy Installation (Historical Reference Only)

For historical documentation—do NOT install Type 1 fonts on modern systems:

Tools and Resources

• FontLab: Professional font editor with comprehensive Type 1 import ($459)
• Glyphs: Mac-native font editor with Type 1 support ($299)
• FontForge: Free, open-source font editor (Windows, Mac, Linux)
• AFDKO: Adobe Font Development Kit for OpenType (free, command-line)
• TransType: FontLab's batch font converter
• FontLab TransType: Professional batch font converter