Last update(s): Fri Apr 14 07:45:58 2006 Thu Mar 23 14:23:25 2017
The PostScript page description language, and PostScript fonts, were developed by Adobe Systems. The language is described in the Adobe `red book'
@String{pub-AW = "Ad{\-d}i{\-s}on-Wes{\-l}ey"}
@String{pub-AW:adr = "Reading, MA, USA"}
@Book{Adobe:1990:PLR,
author = "{Adobe Systems}",
title = "{\POSTSCRIPT} Language Reference Manual",
publisher = pub-AW,
address = pub-AW:adr,
edition = "Second",
pages = "viii + 764",
year = "1990",
ISBN = "0-201-18127-4",
LCCN = "QA76.73.P67 P67 1990",
bibdate = "Tue Dec 14 22:33:36 1993",
acknowledgement = ack-nhfb,
}
and the Type 1 font format is described in the Adobe `black book'
@Manual{Adobe:1990:ATFa,
author = "{Adobe Systems}",
title = "{Adobe} type 1 font format",
organization = pub-ADOBE,
address = pub-ADOBE:adr,
pages = "iii + 101",
year = "1990",
bibdate = "Sun Feb 11 07:52:15 MST 1996",
acknowledgement = ack-nhfb,
annote = "Includes index. ``Version 1.0''--verso t.p. ``Part
number: LPS0064''--verso t.p.",
keywords = "PostScript (Computer program language)",
}
Prior to the publication of the black book, the font format and the required decryption key were secret and proprietary to Adobe, but the pressure of competition from the Apple/Microsoft TrueType font development led them to document and publish the format, allowing other typesetter and font vendors to convert their own fonts to Type 1 format, with the result that there are now of the order of 10,000 Type 1 fonts commercially available from multiple vendors.
Adobe Type 1 fonts are stored in two common formats, .pfa (PostScript Font ASCII) and .pfb (PostScript Font Binary). These contain descriptions of the character shapes, with each character being generated by a small program that calls on other small programs to compute common parts of the characters in the font. In both cases, the character descriptions are encrypted.
Before such a font can be used, it must be rendered into dots in a bitmap, either by the PostScript interpreter, or by a specialized rendering engine, such as Adobe Type Manager, which is used to generate low-resolution screen fonts on Apple Macintosh and on Microsoft Windows systems.
The Type 1 outline files do not contain sufficient information for typesetting with the font, because they have only limited metric data, and nothing about kerning (position adjustments of particular adjacent characters) or ligatures (replacement of adjacent characters by a single character glyph, those for fi, ffi, fl, and ffl being most common in English typography).
This missing information is supplied in additional files, called .afm (Adobe Font Metric) files. These are ASCII files with a well-defined easy-to-parse structure. Some font vendors, such as Adobe, allow them to be freely distributed; others, such as Bitstream, consider them to be restricted by a font license which must be purchased.
PostScript printers generally contain from a dozen to a hundred fonts in .pfb (or equivalent) format in ROM, or in some cases, on disk. However, none that I'm aware of contain the .afm files, so in order to use the printer-resident fonts with your typesetting system, you need to get those .afm files from your printer vendor. Many printer vendors now make these files available on CD-ROMs and at their World-Wide Web sites, together with .ppd (PostScript Printer Description) files that printer and typesetting software can use to gain additional information about the fonts and features of a particular printer model.
In case you are interested in seeing what these files look like, here are some sample font files in the formats described above, using the Nimbus Roman No9 L Regular font (visually identical to Times Roman) kindly released for free public use by URW Software, one of the veteran font vendors. For the binary .pfb file, your Web browser will probably ask for a place to store it on disk, rather than displaying it in the browser window.
The t1utils font utility package by I. Lee Hetherington and Piet Tutelaers provides tools for decoding Type 1 fonts into a human-readable, and editable format ( t1disasm ), reassembling them back into fonts ( t1asm ), for converting between the ASCII and binary formats ( t1ascii and t1binary ), and for converting from Macintosh PostScript format to Adobe PostScript font format ( unpost ).
Commercial font editors, such as Fontographer, can read and write Type 1 font files.
I hereby acknowledge the substantial help of Berthold Horn of Y&Y in preparing this list of font vendors; thanks a bunch, Berthold!