The text-producing systems

LaTeX Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

and

TeX Tex may refer to: People and fictional characters * Tex (nickname), a list of people and fictional characters with the nickname * Joe Tex (1933–1982), stage name of American soul singer Joseph Arrington Jr. Entertainment * ''Tex'', the Italian ...

produce

DVI Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...

files from files written by the user. Those files used to be (and, to a moderate extent, still are) post-processed by a tool called

dvips dvips is a computer program that converts the Device Independent file format (DVI) output of TeX typography into a printable or otherwise presentable form. was written by Tomas Rokicki to produce printable PostScript files from DVI input, and ...

, which converted those DVI files into

PostScript PostScript (PS) is a page description language in the electronic publishing and desktop publishing realm. It is a dynamically typed, concatenative programming language. It was created at Adobe Systems by John Warnock, Charles Geschke, Doug Br ...

files, which are understood by many printers. Some older versions of

with embedded bitmapped fonts, which represented letters and symbols as pictures at a fixed resolution (for instance, at 300 dpi). When such files are printed on newer devices (some with resolution of 1200 dpi), the letters of the files that have bitmapped fonts display a remarkably low quality, with jagged lines on curves and diagonals. One solution to this problem is to substitute the bitmapped fonts with scalable fonts (known among PostScript users as

Type 1 font PostScript fonts are font files encoded in outline font specifications developed by Adobe Systems for professional digital typesetting. This system uses PostScript file format to encode font information. "PostScript fonts" may also separately be ...

s). To remedy this problem of low quality printing, one can use Heiko Oberdiek's utility called pkfix. The input of pkfix is a PostScript file generated by dvips (with versions at 5.58 or newerDocumentation of pkfix on CTAN.
/ref>) and its output is another PostScript file, this time, with the bitmapped fonts substituted by scalable fonts (if possible). Technically speaking, pkfix is a

Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offici ...

script which searches the PostScript file for comments on bitmapped PK fonts (introduced by relatively recent dvips versions), and replaces them with the corresponding Type 1 fonts. Of course, a simpler solution to this problem would be to reprocess the LaTeX/TeX files with recent tools and fonts, but, in most cases, the person that has the given PostScript file isn't the author of the document and doesn't have access to the source files (or, worse, the source files may have been lost during the times).

References

{{reflist Font formats PostScript Software using the LPPL license