Type 1 vs. Type 3 Fonts

Why Type 1 Fonts?

The primary difference between PostScript Type 3 fonts and Type 1 fonts is the way character programs are stored. Type 3 fonts are user-defined fonts which are defined by a series of PostScript operators and operands that display the character. One of the classic examples of Type 3 fonts is the "Computer Modern Romans" font family used by LaTeX.

Type 1 fonts are written to a much stricter syntax than normal PostScript programs. They contain specialized "hints" to direct the font interpreter how to place pixels so the character look good at low resolutions and small sizes. As a results, for documents using Type 1 fonts, the Adobe Type Manager (TM) (ATM) program uses Type 1 outline fonts to automatically create bitmapped fonts of any size for the screen display quickly without embedding the fonts in the PDF document.

However, for Type 3 fonts, in order for the ATM program to display the document properly even when the fonts are unavailable on the current computer, non-ISO Type 1 fonts have to be embedded into the PDF file. This requires additional storage space for the files and it is generally slower to display document with Type 3 fonts. In addition, these documents have poorer resolution. In order to read such document, it is generally required that the user uses a very high magnification level.

How to Generate Type 1 Fonts

As mentioned, it is recommended that you specify Adobe Times Roman, Courier, Helvetica, and Symbol for the entire paper, including mathematics. Avoid using other non-ISO Type 1 fonts. In particular, LaTeX users should utilize the Times Roman PostScript font when formatting their documents for publication. This can be achieved easily by specifying Times font at the documentstyle command:

\documentstyle[times]{article}

Although the mathematics fonts used by LaTeX are not Type 1 fonts, the appearance of the document can improve tremendously if the above command is used in the TeX document. If the author uses LaTeX2e package, it is even possible to use Type 1 fonts for mathematical symbols.

To assist authors to generate PostScript documents using Type 1 fonts, SIGGRAPH have created style sheets for different document preparation packages. We have ftp-ed the style sheets from ftp.siggraph.org and you may access the tar file on this site.