Almost as complex as PostScript itself was PS's handling of
fonts. The rich font
system used the PS graphics primitives to draw characters as
line art, which could then be rendered at any
might sound like a reasonably straightforward concept, but there
are a number of typographic issues that had to be considered.
One is that fonts do not actually scale linearly at small sizes;
features of the characters will become proportionally too large or
small and they start to "look wrong." PostScript avoided this
problem with the inclusion of hints which could be saved
along with the font outlines. Basically they are additional
information in horizontal or vertical bands that help identify the
features in each letter that are important for the rasterizer to
maintain. The result was significantly better-looking fonts even at
low resolution; it was formerly believed that hand-tuned bitmap
fonts were required for this task.
At the time the technology for including these hints in fonts
was carefully guarded, and the hinted fonts were compressed and
encrypted into what Adobe called a Type 1 Font. Type 1 was
effectively a simplification of the PS system to store outline
information only, as opposed to being a complete language (PDF is
similar in this regard). Adobe would then sell licenses to the Type
1 technology at a very high cost to those wanting to add hints to
their own fonts. Those who were happy without hints, or didn't want
to spend the money, were left with the so-called Type 3
Font. Type 3 fonts allowed for all the sophistication of the
PostScript language, but without the standardized approach to
hinting. Other differences further added to the confusion.
The cost of the licensing was considered by many to be too high,
and Adobe continued to stonewall on more attractive rates. It was
this issue that led Apple to design their own system, TrueType, around 1991.
Immediately following the announcement of TrueType, Adobe published
the specification for Type 1 fonts. Retail tools such as Altsys
(now owned by Macromedia) added the ability to create Type 1
fonts. Since then, many free Type 1 fonts have been released; for
instance, the fonts used with the TeX typesetting system are available in this format.
In the early 1990s there
were several other systems for storing outline-based fonts,
developed by Bitstream and Metafont for instance, but none included a
general-purpose printing solution and they were therefore not
widely used as a result.
This information is based on the article Type_1_font from the free encyclopedia Wikipedia and is licensed under the GNU Free Documentation License. On Wikipedia is a list of authors available.