The fontch macros allow the user to change font size and family anywhere in a plain TeX document. Sizes of 8, 10, 12, 14, 20 and 24 points are available. A sans serif family (\sf) is defined in addition to the families already defined in plain TeX. Optional support for Latin Modern T1 and TS1 fonts is given. There are macros for non-latin1 letters and for most TS1 symbols. Math mode always uses CM fonts.

A command for producing doubled-spaced documents is also provided.

The present version of the package is designed to deal with the latest release of the Latin Modern fonts version 1.106. Unfortunately, it can no longer support earlier versions of the fonts, so an obsolete version of the package is retained for users who don't yet have access to the latest version of the fonts.

See also font-selection ofs plnfss.

The author is Rodrigo Medina.