\font primitive:
\font\foo=nonstdfont ... \foo Text set using nonstdfont ...
The name you use (nonstdfont, above) is the name of the
.tfm file for the font you want.
\foo, you need to use
\font again:
\font\fooi=nonstdfont-italic ... \fooi Text set using nonstdfont italic...
This is all very elementary stuff, and serves for simple use of fonts. However, there are wrinkles, the most important of which is the matter of font encodings. Unfortunately, many fonts that have appeared recently simply don’t come in versions using Knuth’s eccentric font encodings — but those encodings are built into Plain TeX, so that some macros of Plain TeX need to be changed to use the fonts. LaTeX gets around all these problems by using a “font selection scheme” — this ‘NFSS’ (‘N’ for ‘new’, as opposed to what LaTeX 2.09 had) carries around with it separate information about the fonts you use, so the changes to encoding-specific commands happen automagically. If you only want to use the EC fonts, you can in principle use the ec-plain bundle, which gives you a version of Plain TeX which you can run in the same way that you run Plain TeX using the original CM fonts, by invoking tex. (Ec-plain also extends the EC fonts, for reasons which aren’t immediately clear, but which might cause problems if you’re hoping to use Type 1 versions of the fonts.) The font_selection package provides a sort of halfway house: it provides font face and size, but not family selection. This gives you considerable freedom, but leaves you stuck with the original CM fonts. It’s a compact solution, within its restrictions. Other Plain TeX approaches to the problem (packages plnfss, fontch and ofs) break out of the Plain TeX model, towards the sort of font selection provided by ConTeXt and LaTeX — font selection that allows you to change family, as well as size and face. The remaining packages all make provision for using encodings other than Knuth’s OT1. Plnfss has a rather basic set of font family details; however, it is capable of using font description (
.fd) files
created for LaTeX. (This is useful, since most modern mechanisms
for integrating outline fonts with TeX generate .fd files
in their process.)
Fontch has special provision for T1 and TS1
encodings, which you select by arcane commands, such as:
\let\LMTone\relax \input fontch.tex
for T1.
Ofs seems to be the most thoroughly thought-through of the alternatives, and can select more than one encoding: as well as T1 it covers the encoding IL2, which is favoured in the Czech Republic and Slovakia. Ofs also covers mathematical fonts, allowing you the dubious pleasure of using fonts such as the pxfonts and txfonts. The pdcmac Plain TeX macro package aims to be a complete document preparation environment, like Eplain. One of its components is a font selection scheme, pdcfsel, which is rather simple but adequately powerful for many uses. The package doesn’t preload fonts: the user is required to declare the fonts the document is going to use, and the package provides commands to select fonts as they’re needed. The distribution includes a configuration to use Adobe ‘standard’ fonts for typesetting text. (Eplain itself seems not to offer a font selection scheme.)This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=fonts-pln