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<head>
<title>UK TeX FAQ -- question label adobetypen</title>
</head><body>
<h3>Adobe font formats</h3>
<!-- type1 type3 -->
<p/>Adobe has specified a number of formats for files to represent fonts
in PostScript files; this question doesn&#8217;t attempt to be encyclopaedic, so
we only discuss the two formats most commonly encountered in the
(La)TeX context, types 1 and 3.  In particular, we don&#8217;t discuss the
OpenType format, whose has many advantages have only in the last year
or two been readily accessible to most (La)TeX users (by means of
  the widely-used <a href="FAQ-xetex.html">XeTeX</a> and the more experimental
  <a href="FAQ-luatex.html">LuaTeX</a>).

<p/>Adobe Type 1 format specifies a means to represent outlines of the glyphs
in a font.  The &#8216;language&#8217; used is closely restricted, to ensure that
the font is rendered as quickly as possible.  (Or rather, as quickly
as possible with Adobe&#8217;s technology at the time the specification was
written: the structure could well be different if it were specified
now.)  The format has long been the basis of the digital type-foundry
business, though nowadays most new fonts are released in OpenType format.
<p/>



<p/>In the (La)TeX context, Type 1 fonts are extremely important.  Apart
from their simple 
availability (there are thousands of commercial Type 1 text fonts around), the
commonest reader for PDF files has long (in effect) <em>insisted</em> on
their use (see below).
<p/>Type 3 fonts have a more forgiving specification.  A wide range of
PostScript operators is permissible, including bitmap specifiers.  Type 3
is therefore the natural format to be used for programs such as
<i>dvips</i> when they auto-generate something to represent
Metafont-generated fonts in a PostScript file.  It&#8217;s Adobe Acrobat Viewer&#8217;s
treatment of bitmap Type 3 fonts that has made direct Metafont output
increasingly unattractive, in recent years.  If you have a PDF
document in which the text looks fuzzy and uneven in Acrobat Reader,
ask Reader for the <code>File</code>-&#62; 
<code>Document Properties</code>-&#62; 
<code>Fonts ...</code>, and it will likely show some font or other as
&#8220;Type 3&#8221; (usually with encoding &#8220;Custom&#8221;).  The problem has
disappeared with version 6 of Acrobat Reader.  See 
<a href="FAQ-dvips-pdf.html">PDF quality</a> for a discussion of
the issue, and for ways of addressing it.
<p/>Type 3 fonts should not entirely be dismissed, however.  Acrobat
Reader&#8217;s failure with them is entirely derived from its failure to use
the anti-aliasing techniques common in TeX-ware.  Choose a
different set of PostScript graphical operators, and you can make pleasing
Type 3 fonts that don&#8217;t &#8220;annoy&#8221; Reader.  For example, you may not
change colour within a Type 1 font glyph, but there&#8217;s no such
restriction on a Type 3 font, which opens opportunities for some
startling effects.
<p/><p>This question on the Web: <a href="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=adobetypen">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=adobetypen</a>
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