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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&rsquo;t attempt to be encyclopaedic, but
we&rsquo;ll discuss the two formats most commonly encountered in the
(La)TeX context, types 1 and 3.
<p>Adobe Type 1 format specifies a means to represent outlines of the glyphs
in a font.  The &lsquo;language&rsquo; used is closely restricted, to ensure that
the font is rendered as quickly as possible.  (Or rather, as quickly
as possible with Adobe&rsquo;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 things are showing signs of change.
<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 <a href="FAQ-dvips-pdf.html">PDF quality</a>).
<p>Type 3 fonts have a more forgiving specification.  A wide range of
PostScript operators is permissible, including bitmaps operators.  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&rsquo;s Adobe Acrobat Viewer&rsquo;s
treatment of bitmap Type 3 fonts that has made direct Metafont output
inreasingly 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>-&gt; 
<code>Document Properties</code>-&gt; 
<code>Fonts ...</code>, and it will show some font or other as &ldquo;Type 3&rdquo;
(usually with encoding &ldquo;Custom&rdquo;).  (This problem has disappeared
with version 6 of Acrobat Reader.)
<p>Type 3 fonts should not entirely be dismissed, however.  Acrobat
Reader&rsquo;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&rsquo;t &ldquo;annoy&rdquo; Reader.  For example, you may not
change colour within a Type 1 font glyph, but there&rsquo;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>
</body>